v3.19.1

Derivative Instruments (Details 3) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gain (Loss) on Sale of Derivatives | [1],[2] | $ 193 | $ 7 | $ 235
Unrealized Gain (Loss) on Derivatives | [3] | (205) | (169) | 1
Gain (Loss) on Derivative Instruments, Net, Pretax | [4] | (12) | (162) | 236
Energy Related Derivative [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gain (Loss) on Sale of Derivatives | [1],[2] | 193 | 7 | 235
Unrealized Gain (Loss) on Derivatives | [3] | (208) | (171) | (1)
Interest Rate Contract [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Unrealized Gain (Loss) on Derivatives | [3] | 3 | 2 | 2
Sales [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gain (Loss) on Derivative Instruments, Net, Pretax | [4],[5],[6] | (369) | (69) | 109
Cost of Sales [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gain (Loss) on Derivative Instruments, Net, Pretax | [4],[5],[6] | 354 | (95) | 125
Interest Expense [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Gain (Loss) on Derivative Instruments, Net, Pretax |  | $ 3 | $ 2 | $ 2
[1] | Does not include the realized value associated with derivative instruments that settle through physical delivery.
[2] | Includes amortization of acquisition date fair value of financial derivative activity related to the acquisition of Champion Energy, Calpine Solutions and North American Power.
[3] | In addition to changes in market value on derivatives not designated as hedges, changes in mark-to-market gain (loss) also includes hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.
[4] | In addition to changes in market value on derivatives not designated as hedges, changes in mark-to-market gain (loss) also includes hedge ineffectiveness and adjustments to reflect changes in credit default risk exposure.
[5] | Does not include the realized value associated with derivative instruments that settle through physical delivery.
[6] | Includes amortization of acquisition date fair value of financial derivative activity related to the acquisition of Champion Energy, Calpine Solutions and North American Power.

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- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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- Definition The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(h)) -URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260 + Details
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- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
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