Derivative Instruments (Details 2) (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative Asset	[1]	$ 402	$ 302
Derivative Liability	[1]	288	443
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		12	40
Derivative Liability		29	10
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		390	262
Derivative Liability		259	433
Energy Related Derivative [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		390	262
Derivative Liability		257	433
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		12	40
Derivative Liability		31	10
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset		12	40
Derivative Liability		$ 29	$ 10

[1] At December 31, 2019 and 2018, we had $191 million and $244 million of collateral under master netting arrangements that were not offset against our derivative instruments on the Consolidated Balance Sheets primarily related to initial margin requirements.