XML 191 R134.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Common Stock (Equity Securities Offering) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Feb. 20, 2018 | Dec. 31, 2018 | Jun. 30, 2018 | Oct. 31, 2016 | Mar. 31, 2018 | Dec. 31, 2018 | Mar. 31, 2016
Forward Contract Indexed to Issuer's Equity [Line Items] |  |  |  |  |  |  |
Maximum value of shares to be issued under ATM program | $ 1,000 |  |  |  |  |  |
Stock Issued During Period, Shares, Dividend Reinvestment Plan |  |  |  |  |  | 2.2 |
Stock Issued During Period, Value, Dividend Reinvestment Plan |  |  |  |  |  | $ 174 |
ATM [Member] |  |  |  |  |  |  |
Forward Contract Indexed to Issuer's Equity [Line Items] |  |  |  |  |  |  |
Settlement Alternatives, Shares |  | 2.6 | 2.6 |  |  | 2.6 |
Proceeds from Issuance or Sale of Equity |  | $ 195 |  |  |  |  |
Equity Forwards [Member] |  |  |  |  |  |  |
Forward Contract Indexed to Issuer's Equity [Line Items] |  |  |  |  |  |  |
Shares offered |  |  |  |  | 21.3 |  |
Sales price |  |  |  |  | $ 75 |  |
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share |  |  |  |  | $ 74.07 |  |
Settlement Alternatives, Shares |  |  |  |  | 21.3 |  |
Shares, Issued |  | 10.6 | 10.6 |  |  | 10.6 |
Proceeds from Issuance or Sale of Equity |  | $ 766 | $ 781 |  |  |  |
Piedmont Natural Gas [Member] |  |  |  |  |  |  |
Forward Contract Indexed to Issuer's Equity [Line Items] |  |  |  |  |  |  |
Shares offered |  |  |  |  |  |  | 10.6
Settlement Alternatives, Shares |  |  |  |  |  |  | 10.6
Common stock issuances, including dividend reinvestment and employee benefits (in shares) |  |  |  | 10.6 |  |  |
Proceeds from Issuance or Sale of Equity |  |  |  | $ 723 |  |  |
Wells Fargo Bank [Member] | ATM [Member] |  |  |  |  |  |  |
Forward Contract Indexed to Issuer's Equity [Line Items] |  |  |  |  |  |  |
Shares offered |  |  | 1.3 |  |  |  |
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share |  |  | $ 72.02 |  |  |  |
Citibank [Member] | ATM [Member] |  |  |  |  |  |  |
Forward Contract Indexed to Issuer's Equity [Line Items] |  |  |  |  |  |  |
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share |  |  | $ 78.71 |  |  |  |

X
- Definition Maximum value of shares to be issued under ATM program of its common stock through an at-the-market offering program, including an equity forward sales component. + References No definition available. + Details
Name: | duk_MaximumValueOfSharesToBeIssuedUnderATMProgram
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Price per share in connection with the forward sale agreements under which the company agreed to issue and sell to the counterparties + References No definition available. + Details
Name: | duk_Salesprice
Namespace Prefix: | duk_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The per share price of the Company's stock at which the contract holder of the freestanding contract has the right to purchase or sell the Company's stock at a future date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 50 -Paragraph 5 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=109262807&loc=d3e22047-110879 + Details
Name: | us-gaap_ForwardContractIndexedToIssuersEquityForwardRate
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of issuer's shares to which the forward contract is indexed. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 50 -Paragraph 5 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008 + Details
Name: | us-gaap_ForwardContractIndexedToIssuersEquityIndexedShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ForwardContractIndexedToIssuersEquityLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares as a settlement alternative for each freestanding forward contract. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008 + Details
Name: | us-gaap_ForwardContractIndexedToIssuersEquitySettlementAlternativesSharesAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash inflow from the issuance of common stock, preferred stock, treasury stock, stock options, and other types of equity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOrSaleOfEquity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
Name: | us-gaap_SharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares issued during the period from a dividend reinvestment plan (DRIP). A dividend reinvestment plan allows the shareholders to reinvest dividends paid to them by the entity on new issues of stock by the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of stock issued during the period from a dividend reinvestment plan (DRIP). A dividend reinvestment plan allows the holder of the stock to reinvest dividends paid to them by the entity on new issues of stock by the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
Name: | us-gaap_StockIssuedDuringPeriodValueDividendReinvestmentPlan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis=duk_ATMMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis=duk_EquityForwardsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=duk_PiedmontNaturalGasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=duk_WellsFargoBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=duk_CitibankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |