v2.4.0.6

Fair Value of Financial Assets and Liabilities (Tables) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2013 | Mar. 31, 2012 | Dec. 31, 2012
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  | March 31, 2013
(in millions) |  | Total Fair Value | Level 1 |  | Level 2 |  | Level 3
Investments in available-for-sale auction rate securities(a) |  | $ | 28 |  | $ | ― |  | $ | ― |  | $ | 28
Nuclear decommissioning trust fund equity securities |  |  | 3,104 |  |  | 3,026 |  |  | 57 |  |  | 21
Nuclear decommissioning trust fund debt securities |  |  | 1,432 |  |  | 356 |  |  | 1,027 |  |  | 49
Other trading and available-for-sale equity securities(b) |  |  | 93 |  |  | 84 |  |  | 9 |  |  | ―
Other trading and available-for-sale debt securities(c) |  |  | 634 |  |  | 94 |  |  | 540 |  |  | ―
Derivative assets(b) |  |  | 75 |  |  | 1 |  |  | 20 |  |  | 54
| Total assets |  |  | 5,366 |  |  | 3,561 |  |  | 1,653 |  |  | 152
Derivative liabilities(d) |  |  | (611) |  |  | (77) |  |  | (398) |  |  | (136)
| Net assets |  | $ | 4,755 |  | $ | 3,484 |  | $ | 1,255 |  | $ | 16
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Investments in available-for-sale auction rate securities(a) |  | $ | 29 |  | $ | ― |  | $ | ― |  | $ | 29
Nuclear decommissioning trust fund equity securities |  |  | 2,837 |  |  | 2,762 |  |  | 54 |  |  | 21
Nuclear decommissioning trust fund debt securities |  |  | 1,405 |  |  | 317 |  |  | 1,040 |  |  | 48
Other trading and available-for-sale equity securities(b) |  |  | 72 |  |  | 63 |  |  | 9 |  |  | ―
Other trading and available-for-sale debt securities(c) |  |  | 602 |  |  | 40 |  |  | 562 |  |  | ―
Derivative assets(b) |  |  | 103 |  |  | 18 |  |  | 22 |  |  | 63
| Total assets |  |  | 5,048 |  |  | 3,200 |  |  | 1,687 |  |  | 161
Derivative liabilities(d) |  |  | (756) |  |  | (17) |  |  | (591) |  |  | (148)
| Net assets |  | $ | 4,292 |  | $ | 3,183 |  | $ | 1,096 |  | $ | 13
(a) | Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b) | Included in Other within Current Assets and Other within Investments and Other Assets on the Condensed Consolidated Balance Sheet.
(c) | Included in Other within Investments and Other Assets and Short-term Investments on the Condensed Consolidated Balance Sheets.
(d) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs |
|  |  | Three Months Ended March 31, 2013
(in millions) | Available-for-Sale Auction Rate Securities |  | Available-for-Sale NDTF Investments |  | Derivatives (net) |  | Total
Balance at December 31, 2012 | $ | 29 |  | $ | 69 |  | $ | (85) |  | $ | 13
| Total pre-tax realized or unrealized gains (losses) included in earnings: |  |  |  |  |  |  |  |  |  |  |
|  | Regulated electric |  | ― |  |  | ― |  |  | (6) |  |  | (6)
|  | Revenue, nonregulated electric, natural gas, and other |  | ― |  |  | ― |  |  | (4) |  |  | (4)
| Total pre-tax gains included in other comprehensive income: |  |  |  |  |  |  |  |  |  |  |
|  | Losses on available for sale securities and other |  | (1) |  |  | ― |  |  | ― |  |  | (1)
| Purchases, sales, issuances and settlements: |  |  |  |  |  |  |  |  |  |  |
|  | Issuances |  | ― |  |  | ― |  |  | 6 |  |  | 6
|  | Settlements |  | ― |  |  | ― |  |  | 7 |  |  | 7
| Total gains included on the Consolidated Balance Sheet as regulatory asset or liability |  | ― |  |  | 1 |  |  | ― |  |  | 1
Balance at March 31, 2013 | $ | 28 |  | $ | 70 |  | $ | (82) |  | $ | 16
Pre-tax amounts included in the Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013 |  |  |  |  |  |  |  |  |  |  |
|  | Regulated electric | $ | ― |  | $ | ― |  | $ | 1 |  |  | 1
|  | Revenue, nonregulated electric, natural gas, and other |  | ― |  |  | ― |  |  | (10) |  |  | (10)
Total | $ | ― |  | $ | ― |  | $ | (9) |  | $ | (9)
|  |  | Three Months Ended March 31, 2012
(in millions) | Available-for-Sale Auction Rate Securities |  | Available-for-Sale NDTF Investments |  | Derivatives (net) |  | Total
Balance at December 31, 2011 | $ | 71 |  | $ | 53 |  | $ | (39) |  | $ | 85
| Total pre-tax realized or unrealized gains (losses) included in earnings: |  |  |  |  |  |  |  |  |  |  |
|  | Regulated electric |  | ― |  |  | ― |  |  | 8 |  |  | 8
|  | Revenue, nonregulated electric, natural gas, and other |  | ― |  |  | ― |  |  | (2) |  |  | (2)
| Total pre-tax gains included in other comprehensive income: |  |  |  |  |  |  |  |  |  |  |
|  | Gains on available for sale securities and other |  | 1 |  |  | ― |  |  | ― |  |  | 1
| Purchases, sales, issuances and settlements: |  |  |  |  |  |  |  |  |  |  |
|  | Purchases |  | ― |  |  | 2 |  |  | ― |  |  | 2
|  | Settlements |  | ― |  |  | ― |  |  | (9) |  |  | (9)
| Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  | ― |  |  | 1 |  |  | ― |  |  | 1
Balance at March 31, 2012 | $ | 72 |  | $ | 56 |  | $ | (42) |  | $ | 86
Schedule of Long-term debt, including current |
|  |  |  | March 31, 2013 |  | December 31, 2012
(in millions) | Book Value |  | Fair Value |  | Book Value |  | Fair Value
Duke Energy (a) | $ | 39,662 |  | $ | 44,068 |  | $ | 39,461 |  | $ | 44,001
Duke Energy Carolinas(b) |  | 8,740 |  |  | 10,036 |  |  | 8,741 |  |  | 10,096
Progress Energy |  | 14,224 |  |  | 16,276 |  |  | 14,428 |  |  | 16,563
Duke Energy Progress |  | 5,336 |  |  | 5,757 |  |  | 4,840 |  |  | 5,277
Duke Energy Florida |  | 4,894 |  |  | 5,730 |  |  | 5,320 |  |  | 6,222
Duke Energy Ohio |  | 1,994 |  |  | 2,142 |  |  | 1,997 |  |  | 2,117
Duke Energy Indiana |  | 3,702 |  |  | 4,228 |  |  | 3,702 |  |  | 4,268
(a) | Includes book value of Non-recourse long-term debt of variable interest entities of $1,255 million and $852 million March 31, 2013 and December 31, 2012, respectively.
(b) | Includes book value of Non-recourse long-term debt of variable interest entities of $300 million at both March 31, 2013 and December 31, 2012, respectively.
Quantitative Information Table - Level 3 |
|  |  | March 31, 2013
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (85) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.84 | $ | 10.30
FERC mitigation power sale agreements |  |  | (10) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 54.56
Financial transmission rights (FTRs) |  |  | 4 |  | RTO market pricing |  | FTR price |  |  | (0.42) | - | 12.72
Commodity power contracts |  |  | 17 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 28.40 | - | 81.60
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 122.64
Commodity capacity option contracts |  |  | 2 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 31.15 | - | 81.60
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.18 | - | 54.56
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Commodity power contracts |  | $ | 25 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.40 | - | 61.35
Commodity natural gas contracts |  |  | (23) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.98 | - | 4.69
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 4 |  | RTO market pricing |  | FTR price |  | $ | (0.42) | $ | 12.72
|  |  | December 31, 2012
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (53) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.33 | $ | 9.99
FERC mitigation power sale agreements |  |  | (23) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Financial transmission rights (FTRs) |  |  | 11 |  | RTO market pricing |  | FTR price |  |  | 23.63 | - | 39.22
Commodity power contracts |  |  | (8) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 24.82 | - | 77.96
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 105.36
Commodity capacity option contracts |  |  | 3 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 4.68 | - | 77.96
Reserves |  |  | (12) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (12) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 25.83 | - | 48.69
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 1 |  | RTO market pricing |  | FTR price |  | $ | 27.17 | $ | 39.22
Commodity power contracts |  |  | (1) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.90 | - | 57.50
Commodity natural gas contracts |  |  | 5 |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.30 | - | 4.51
Reserves |  |  | (11) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 10 |  | RTO market pricing |  | FTR price |  | $ | 23.63 | $ | 35.43
Duke Energy Carolinas [Member] |  |  |
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  |  | March 31, 2013
(in millions) | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Investments in available-for-sale auction rate securities(a) |  | $ | 3 |  | $ | ― |  | $ | ― |  | $ | 3
Nuclear decommissioning trust fund equity securities |  |  | 1,734 |  |  | 1,663 |  |  | 50 |  |  | 21
Nuclear decommissioning trust fund debt securities |  |  | 785 |  |  | 180 |  |  | 556 |  |  | 49
| Total assets |  | $ | 2,522 |  | $ | 1,843 |  | $ | 606 |  | $ | 73
Derivative liabilities(b) |  |  | (5) |  |  | ― |  |  | ― |  |  | (5)
| Net assets |  | $ | 2,517 |  | $ | 1,843 |  | $ | 606 |  | $ | 68
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Investments in available-for-sale auction rate securities(a) |  | $ | 3 |  | $ | ― |  | $ | ― |  | $ | 3
Nuclear decommissioning trust fund equity securities |  |  | 1,592 |  |  | 1,523 |  |  | 48 |  |  | 21
Nuclear decommissioning trust fund debt securities |  |  | 762 |  |  | 155 |  |  | 559 |  |  | 48
| Total assets |  | $ | 2,357 |  | $ | 1,678 |  | $ | 607 |  | $ | 72
Derivative liabilities(b) |  |  | (12) |  |  | ― |  |  | ― |  |  | (12)
| Net Assets |  | $ | 2,345 |  | $ | 1,678 |  | $ | 607 |  | $ | 60
(a) | Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheet.
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs |
|  |  | Three Months Ended March 31,2013
|  |  | Available-for-Sale Auction Rate Securities |  | Available-for-Sale NDTF Investments |  | Derivatives (net) |  | Total
Balance at December 31, 2012 | $ | 3 |  | $ | 69 |  | $ | (12) |  | $ | 60
| Purchases, sales, issuances and settlements: |  |  |  |  |  |  |  |  |  |  |
|  | Settlements |  | ― |  |  | ― |  |  | 7 |  |  | 7
| Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  | ― |  |  | 1 |  |  | ― |  |  | 1
Balance at March 31, 2013 | $ | 3 |  | $ | 70 |  | $ | (5) |  | $ | 68
Pre-tax amounts included in the Condensed Consolidated Statements of Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013 |  |  |  |  |  |  |  |  |  |  |
|  | Regulated electric | $ | ― |  | $ | ― |  | $ | (5) |  |  | (5)
Total | $ | ― |  | $ | ― |  | $ | (5) |  | $ | (5)
|  |  | Three Months Ended March 31, 2012
|  |  | Available-for-Sale Auction Rate Securities |  | Available-for-Sale NDTF Investments |  | Derivatives (net) |  | Total
Balance at December 31, 2011 | $ | 12 |  | $ | 53 |  | $ | ― |  | $ | 65
| Purchases, sales, issuances and settlements: |  |  |  |  |  |  |  |  |  |  |
|  | Purchases |  | ― |  |  | 2 |  |  | ― |  |  | 2
| Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  | ― |  |  | 1 |  |  | ― |  |  | 1
Balance at March 31, 2012 | $ | 12 |  | $ | 56 |  | $ | ― |  | $ | 68
Quantitative Information Table - Level 3 |
|  |  | March 31, 2013
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (85) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.84 | $ | 10.30
FERC mitigation power sale agreements |  |  | (10) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 54.56
Financial transmission rights (FTRs) |  |  | 4 |  | RTO market pricing |  | FTR price |  |  | (0.42) | - | 12.72
Commodity power contracts |  |  | 17 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 28.40 | - | 81.60
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 122.64
Commodity capacity option contracts |  |  | 2 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 31.15 | - | 81.60
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.18 | - | 54.56
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Commodity power contracts |  | $ | 25 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.40 | - | 61.35
Commodity natural gas contracts |  |  | (23) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.98 | - | 4.69
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 4 |  | RTO market pricing |  | FTR price |  | $ | (0.42) | $ | 12.72
|  |  | December 31, 2012
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (53) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.33 | $ | 9.99
FERC mitigation power sale agreements |  |  | (23) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Financial transmission rights (FTRs) |  |  | 11 |  | RTO market pricing |  | FTR price |  |  | 23.63 | - | 39.22
Commodity power contracts |  |  | (8) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 24.82 | - | 77.96
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 105.36
Commodity capacity option contracts |  |  | 3 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 4.68 | - | 77.96
Reserves |  |  | (12) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (12) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 25.83 | - | 48.69
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 1 |  | RTO market pricing |  | FTR price |  | $ | 27.17 | $ | 39.22
Commodity power contracts |  |  | (1) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.90 | - | 57.50
Commodity natural gas contracts |  |  | 5 |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.30 | - | 4.51
Reserves |  |  | (11) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 10 |  | RTO market pricing |  | FTR price |  | $ | 23.63 | $ | 35.43
Progress Energy [Member] |  |  |
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  | March 31, 2013
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Nuclear decommissioning trust fund equity securities |  | $ | 1,369 |  | $ | 1,363 |  | $ | 6 |  | $ | ―
Nuclear decommissioning trust fund debt securities and other |  |  | 648 |  |  | 177 |  |  | 471 |  |  | ―
Other trading and available-for-sale debt securities and other(a) |  |  | 60 |  |  | 20 |  |  | 40 |  |  | ―
Derivative assets(b) |  |  | 15 |  |  | ― |  |  | 15 |  |  | ―
| Total assets |  |  | 2,092 |  |  | 1,560 |  |  | 532 |  |  | ―
Derivative liabilities(c) |  |  | (269) |  |  | ― |  |  | (238) |  |  | (31)
| Net assets |  | $ | 1,823 |  | $ | 1,560 |  | $ | 294 |  | $ | (31)
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Nuclear decommissioning trust fund equity securities |  | $ | 1,245 |  | $ | 1,239 |  | $ | 6 |  | $ | ―
Nuclear decommissioning trust fund debt securities and other |  |  | 643 |  |  | 162 |  |  | 481 |  |  | ―
Other trading and available-for-sale debt securities and other(a) |  |  | 57 |  |  | 17 |  |  | 40 |  |  | ―
Derivative assets(b) |  |  | 11 |  |  | ― |  |  | 11 |  |  | ―
| Total assets |  |  | 1,956 |  |  | 1,418 |  |  | 538 |  |  | ―
Derivative liabilities(c) |  |  | (440) |  |  | ― |  |  | (402) |  |  | (38)
| Net assets |  | $ | 1,516 |  | $ | 1,418 |  | $ | 136 |  | $ | (38)
(a) | Included in Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(b) | Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(c) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs |
|  |  |  | Three Months Ended March 31, 2013
(in millions) |  | Derivatives (net)
Balance at December 31, 2012 |  | $ | (38)
| Purchases, sales, issuances and settlements: |  |  |
|  | Issuances |  |  | 6
| Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  |  | 1
Balance at March 31, 2013 |  | $ | (31)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013 |  |  |
|  | Regulated electric |  | $ | 6
Total |  | $ | 6
|  |  |  | Three Months Ended March 31, 2012
(in millions) |  | Derivatives (net)
Balance at December 31, 2011 |  | $ | (24)
| Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  |  | (3)
Balance at March 31, 2012 |  | $ | (27)
Quantitative Information Table - Level 3 |
|  |  | March 31, 2013
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (85) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.84 | $ | 10.30
FERC mitigation power sale agreements |  |  | (10) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 54.56
Financial transmission rights (FTRs) |  |  | 4 |  | RTO market pricing |  | FTR price |  |  | (0.42) | - | 12.72
Commodity power contracts |  |  | 17 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 28.40 | - | 81.60
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 122.64
Commodity capacity option contracts |  |  | 2 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 31.15 | - | 81.60
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.18 | - | 54.56
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Commodity power contracts |  | $ | 25 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.40 | - | 61.35
Commodity natural gas contracts |  |  | (23) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.98 | - | 4.69
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 4 |  | RTO market pricing |  | FTR price |  | $ | (0.42) | $ | 12.72
|  |  | December 31, 2012
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (53) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.33 | $ | 9.99
FERC mitigation power sale agreements |  |  | (23) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Financial transmission rights (FTRs) |  |  | 11 |  | RTO market pricing |  | FTR price |  |  | 23.63 | - | 39.22
Commodity power contracts |  |  | (8) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 24.82 | - | 77.96
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 105.36
Commodity capacity option contracts |  |  | 3 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 4.68 | - | 77.96
Reserves |  |  | (12) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (12) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 25.83 | - | 48.69
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 1 |  | RTO market pricing |  | FTR price |  | $ | 27.17 | $ | 39.22
Commodity power contracts |  |  | (1) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.90 | - | 57.50
Commodity natural gas contracts |  |  | 5 |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.30 | - | 4.51
Reserves |  |  | (11) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 10 |  | RTO market pricing |  | FTR price |  | $ | 23.63 | $ | 35.43
Duke Energy Progress [Member] |  |  |
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  | March 31, 2013
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Nuclear decommissioning trust fund equity securities |  | $ | 894 |  | $ | 894 |  | $ | ― |  | $ | ―
Nuclear decommissioning trust fund debt securities and other |  |  | 453 |  |  | 123 |  |  | 330 |  |  | ―
Other trading and available-for-sale debt securities and other(a) |  |  | 4 |  |  | 4 |  |  | ― |  |  | ―
Derivative assets(b) |  |  | 5 |  |  | ― |  |  | 5 |  |  | ―
| Total assets |  |  | 1,356 |  |  | 1,021 |  |  | 335 |  |  | ―
Derivative liabilities(c) |  |  | (98) |  |  | ― |  |  | (67) |  |  | (31)
| Net assets |  | $ | 1,258 |  | $ | 1,021 |  | $ | 268 |  | $ | (31)
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Nuclear decommissioning trust fund equity securities |  | $ | 811 |  | $ | 811 |  | $ | ― |  | $ | ―
Nuclear decommissioning trust fund debt securities and other |  |  | 448 |  |  | 119 |  |  | 329 |  |  | ―
Other trading and available-for-sale debt securities and other(a) |  |  | 3 |  |  | 3 |  |  | ― |  |  | ―
Derivative assets(b) |  |  | 2 |  |  | ― |  |  | 2 |  |  | ―
| Total assets |  |  | 1,264 |  |  | 933 |  |  | 331 |  |  | ―
Derivative liabilities(c) |  |  | (166) |  |  | ― |  |  | (128) |  |  | (38)
| Net assets |  | $ | 1,098 |  | $ | 933 |  | $ | 203 |  | $ | (38)
(a) | Included in Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(b) | Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(c) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs |
|  |  |  | Three Months Ended March 31, 2013
(in millions) |  | Derivatives (net)
Balance at December 31, 2012 |  | $ | (38)
| Purchases, sales, issuances and settlements: |  |  |
|  | Issuances |  |  | 6
| Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  |  | 1
Balance at March 31, 2013 |  | $ | (31)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013 |  |  |
|  | Regulated electric |  | $ | 6
Total |  | $ | 6
|  |  |  | Three Months Ended March 31, 2012
(in millions) |  | Derivatives (net)
Balance at December 31, 2011 |  | $ | (24)
| Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  |  | (3)
Balance at March 31, 2012 |  | $ | (27)
Quantitative Information Table - Level 3 |
|  |  | March 31, 2013
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (85) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.84 | $ | 10.30
FERC mitigation power sale agreements |  |  | (10) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 54.56
Financial transmission rights (FTRs) |  |  | 4 |  | RTO market pricing |  | FTR price |  |  | (0.42) | - | 12.72
Commodity power contracts |  |  | 17 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 28.40 | - | 81.60
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 122.64
Commodity capacity option contracts |  |  | 2 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 31.15 | - | 81.60
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.18 | - | 54.56
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Commodity power contracts |  | $ | 25 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.40 | - | 61.35
Commodity natural gas contracts |  |  | (23) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.98 | - | 4.69
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 4 |  | RTO market pricing |  | FTR price |  | $ | (0.42) | $ | 12.72
|  |  | December 31, 2012
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (53) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.33 | $ | 9.99
FERC mitigation power sale agreements |  |  | (23) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Financial transmission rights (FTRs) |  |  | 11 |  | RTO market pricing |  | FTR price |  |  | 23.63 | - | 39.22
Commodity power contracts |  |  | (8) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 24.82 | - | 77.96
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 105.36
Commodity capacity option contracts |  |  | 3 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 4.68 | - | 77.96
Reserves |  |  | (12) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (12) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 25.83 | - | 48.69
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 1 |  | RTO market pricing |  | FTR price |  | $ | 27.17 | $ | 39.22
Commodity power contracts |  |  | (1) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.90 | - | 57.50
Commodity natural gas contracts |  |  | 5 |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.30 | - | 4.51
Reserves |  |  | (11) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 10 |  | RTO market pricing |  | FTR price |  | $ | 23.63 | $ | 35.43
Duke Energy Florida [Member] |  |  |
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  | March 31, 2013
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Nuclear decommissioning trust fund equity securities |  | $ | 474 |  | $ | 468 |  | $ | 6 |  | $ | ―
Nuclear decommissioning trust fund debt securities and other |  |  | 196 |  |  | 54 |  |  | 142 |  |  | ―
Other trading and available-for-sale debt securities and other(a) |  |  | 45 |  |  | 5 |  |  | 40 |  |  | ―
Derivative assets(b) |  |  | 10 |  |  | ― |  |  | 10 |  |  | ―
| Total assets |  |  | 725 |  |  | 527 |  |  | 198 |  |  | ―
Derivative liabilities(c) |  |  | (167) |  |  | ― |  |  | (167) |  |  | ―
| Net assets |  | $ | 558 |  | $ | 527 |  | $ | 31 |  | $ | ―
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Nuclear decommissioning trust fund equity securities |  | $ | 435 |  | $ | 429 |  | $ | 6 |  | $ | ―
Nuclear decommissioning trust fund debt securities and other |  |  | 194 |  |  | 43 |  |  | 151 |  |  | ―
Other trading and available-for-sale debt securities and other(a) |  |  | 43 |  |  | 3 |  |  | 40 |  |  | ―
Derivative assets(b) |  |  | 9 |  |  | ― |  |  | 9 |  |  | ―
| Total assets |  |  | 681 |  |  | 475 |  |  | 206 |  |  | ―
Derivative liabilities(c) |  |  | (270) |  |  | ― |  |  | (270) |  |  | ―
| Net assets (liabilities) |  | $ | 411 |  | $ | 475 |  | $ | (64) |  | $ | ―
(a) | Included in Other within Investments and Other Assets in the Condensed Balance Sheets.
(b) | Included in Other Current Assets within Current Assets and Other within Investments and Other Assets in the Condensed Balance Sheets.
(c) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Balance Sheets
Duke Energy Ohio [Member] |  |  |
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  | March 31, 2013
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Derivative assets(a) |  | $ | 19 |  | $ | 8 |  | $ | 2 |  | $ | 9
Derivative liabilities(b) |  |  | (94) |  |  | (72) |  |  | (8) |  |  | (14)
| Net liabilities |  | $ | (75) |  | $ | (64) |  | $ | (6) |  | $ | (5)
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Derivative assets(a) |  | $ | 59 |  | $ | 48 |  | $ | 2 |  | $ | 9
Derivative liabilities(b) |  |  | (38) |  |  | (15) |  |  | (8) |  |  | (15)
| Net assets (liabilities) |  | $ | 21 |  | $ | 33 |  | $ | (6) |  | $ | (6)
(a) | Included in Other within Current Assets and Other within Investments and Other Assets in the Condensed Consolidated Balance Sheets.
(b) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities in the Condensed Consolidated Balance Sheets.
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs |
|  |  |  | Three Months Ended March 31, 2013
(in millions) |  | Derivatives (net)
Balance at December 31, 2012 |  | $ | (6)
| Total pre-tax realized or unrealized gains (losses) included in earnings: |  |  |
|  | Revenue, nonregulated electric, natural gas, and other |  |  | 4
| Purchases, sales, issuances and settlements: |  |  |
|  | Settlements |  |  | (3)
Balance at March 31, 2013 |  | $ | (5)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2013: |  |  |
|  | Revenue, non-regulated electric and other |  | $ | (2)
Total |  | $ | (2)
|  |  |  | Three Months Ended March 31, 2012
(in millions) |  | Derivatives (net)
Balance at December 31, 2011 |  | $ | (3)
| Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  |  | (1)
Balance at March 31, 2012 |  | $ | (4)
Pre-tax amounts included in the Condensed Consolidated Statements of Operations and Comprehensive Income related to Level 3 measurements outstanding at March 31, 2012: |  |  |
|  | Revenue, non-regulated electric and other |  | $ | 1
Total |  | $ | 1
Quantitative Information Table - Level 3 |
|  |  | March 31, 2013
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (85) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.84 | $ | 10.30
FERC mitigation power sale agreements |  |  | (10) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 54.56
Financial transmission rights (FTRs) |  |  | 4 |  | RTO market pricing |  | FTR price |  |  | (0.42) | - | 12.72
Commodity power contracts |  |  | 17 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 28.40 | - | 81.60
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 122.64
Commodity capacity option contracts |  |  | 2 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 31.15 | - | 81.60
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.18 | - | 54.56
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Commodity power contracts |  | $ | 25 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.40 | - | 61.35
Commodity natural gas contracts |  |  | (23) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.98 | - | 4.69
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 4 |  | RTO market pricing |  | FTR price |  | $ | (0.42) | $ | 12.72
|  |  | December 31, 2012
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (53) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.33 | $ | 9.99
FERC mitigation power sale agreements |  |  | (23) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Financial transmission rights (FTRs) |  |  | 11 |  | RTO market pricing |  | FTR price |  |  | 23.63 | - | 39.22
Commodity power contracts |  |  | (8) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 24.82 | - | 77.96
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 105.36
Commodity capacity option contracts |  |  | 3 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 4.68 | - | 77.96
Reserves |  |  | (12) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (12) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 25.83 | - | 48.69
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 1 |  | RTO market pricing |  | FTR price |  | $ | 27.17 | $ | 39.22
Commodity power contracts |  |  | (1) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.90 | - | 57.50
Commodity natural gas contracts |  |  | 5 |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.30 | - | 4.51
Reserves |  |  | (11) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 10 |  | RTO market pricing |  | FTR price |  | $ | 23.63 | $ | 35.43
Duke Energy Indiana [Member] |  |  |
Fair Value Disclosures [Line Items] |  |  |
Fair Value Measurement Amounts For Assets And Liabilities |
|  |  | March 31, 2013
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Available-for-sale equity securities(a) |  | $ | 54 |  | $ | 54 |  | $ | ― |  | $ | ―
Available-for-sale debt securities(a) |  |  | 29 |  |  | ― |  |  | 29 |  |  | ―
Derivative assets(b) |  |  | 5 |  |  | 1 |  |  | ― |  |  | 4
| Total assets |  |  | 88 |  |  | 55 |  |  | 29 |  | $ | 4
Derivative liabilities(c) |  |  | (55) |  |  | ― |  |  | (55) |  |  | ―
| Net assets (liabilities) |  | $ | 33 |  | $ | 55 |  | $ | (26) |  | $ | 4
|  |  | December 31, 2012
(in millions) |  | Total Fair Value |  | Level 1 |  | Level 2 |  | Level 3
Available-for-sale equity securities(a) |  | $ | 49 |  | $ | 49 |  | $ | ― |  | $ | ―
Available-for-sale debt securities(a) |  |  | 29 |  |  | ― |  |  | 29 |  |  | ―
Derivative assets(b) |  |  | 10 |  |  | ― |  |  | ― |  |  | 10
| Total assets |  |  | 88 |  |  | 49 |  |  | 29 |  | $ | 10
Derivative liabilities(c) |  |  | (63) |  |  | ― |  |  | (63) |  |  | ―
| Net assets (liabilities) |  | $ | 25 |  | $ | 49 |  | $ | (34) |  | $ | 10
(a) | Included in Other within Investments and Other Assets on the Condensed Consolidated Balance Sheets.
(b) | Included in Other within Current Assets on the Condensed Consolidated Balance Sheets.
(c) | Included in Other within Current Liabilities and Other within Deferred Credits and Other Liabilities on the Condensed Consolidated Balance Sheets.
Reconciliation Of Assets And Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs |
|  |  |  | Three Months Ended March 31, 2013
(in millions) | Derivatives (net)
Balance at December 31, 2012 | $ | 10
| Total pre-tax realized or unrealized gains (losses) included in earnings: |  |
|  | Regulated electric |  |  | (5)
| Total losses included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  | (1)
Balance at March 31, 2013 | $ | 4
|  |  |  | Three Months Ended March 31, 2012
(in millions) | Derivatives (net)
Balance at December 31, 2011 |  | $ | 4
| Total pre-tax realized or unrealized gains (losses) included in earnings: |  |
|  | Regulated electric |  |  | 8
| Purchases, sales, issuances and settlements: |  |
|  | Settlements |  | (10)
| Total gains included on the Condensed Consolidated Balance Sheet as regulatory asset or liability |  | 1
Balance at March 31, 2012 | $ | 3
Quantitative Information Table - Level 3 |
|  |  | March 31, 2013
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (85) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.84 | $ | 10.30
FERC mitigation power sale agreements |  |  | (10) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 54.56
Financial transmission rights (FTRs) |  |  | 4 |  | RTO market pricing |  | FTR price |  |  | (0.42) | - | 12.72
Commodity power contracts |  |  | 17 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 28.40 | - | 81.60
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 122.64
Commodity capacity option contracts |  |  | 2 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 31.15 | - | 81.60
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.18 | - | 54.56
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (26) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.13 | - | 4.54
FERC mitigation power sale agreements |  |  | (5) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.35 | - | 48.68
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Commodity power contracts |  | $ | 25 |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 28.40 | - | 61.35
Commodity natural gas contracts |  |  | (23) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.98 | - | 4.69
Reserves |  |  | (7) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 4 |  | RTO market pricing |  | FTR price |  | $ | (0.42) | $ | 12.72
|  |  | December 31, 2012
Investment Type |  | Fair Value (in millions) |  | Valuation Technique |  | Unobservable Input |  | Range
Duke Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (53) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 2.33 | $ | 9.99
FERC mitigation power sale agreements |  |  | (23) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Financial transmission rights (FTRs) |  |  | 11 |  | RTO market pricing |  | FTR price |  |  | 23.63 | - | 39.22
Commodity power contracts |  |  | (8) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 24.82 | - | 77.96
Commodity capacity contracts |  |  | (3) |  | Discounted cash flow |  | Forward capacity curves - price per MW day |  |  | 95.16 | - | 105.36
Commodity capacity option contracts |  |  | 3 |  | Discounted cash flow |  | Forward capacity option curves - price per MW day |  |  | 4.68 | - | 77.96
Reserves |  |  | (12) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Carolinas |  |  |  |  |  |  |  |  |  |  |  |
FERC mitigation power sale agreements |  | $ | (12) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  | $ | 25.83 | - | 48.69
Progress Energy |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Progress |  |  |  |  |  |  |  |  |  |  |  |
Commodity natural gas contracts |  | $ | (27) |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  | $ | 4.07 | - | 4.45
FERC mitigation power sale agreements |  |  | (11) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.83 | - | 48.69
Duke Energy Ohio |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 1 |  | RTO market pricing |  | FTR price |  | $ | 27.17 | $ | 39.22
Commodity power contracts |  |  | (1) |  | Discounted cash flow |  | Forward electricity curves - price per MWh |  |  | 25.90 | - | 57.50
Commodity natural gas contracts |  |  | 5 |  | Discounted cash flow |  | Forward natural gas curves - price per MMBtu |  |  | 3.30 | - | 4.51
Reserves |  |  | (11) |  |  |  | Bid-ask spreads, implied volatility, probability of default |  |  |  |  |
Duke Energy Indiana |  |  |  |  |  |  |  |  |  |  |  |
Financial transmission rights (FTRs) |  | $ | 10 |  | RTO market pricing |  | FTR price |  | $ | 23.63 | $ | 35.43

X
- Details
Name: | duk_FairValueDisclosuresLineItems
Namespace Prefix: | duk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure for the fair value amount of long-term debt. + References No definition available. + Details
Name: | duk_ScheduleOfLongTermDebtFairValueTableTextBlock
Namespace Prefix: | duk_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the inputs and valuation techniques used to measure fair value, and a discussion of changes in valuation techniques and related inputs, if any, used to measure similar assets in prior periods (non-recurring basis) by class of asset or liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 33 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisValuationTechniquesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the fair value measurement of assets using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income (loss), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19279-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of assets and liabilities, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, that are measured at fair value on a recurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19190-110258 + Details
Name: | us-gaap_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration