v3.19.1

Derivative Instruments (Details 3) (Details) - USD ($)
$ in Millions

12 Months Ended

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.

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.

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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

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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

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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)
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