Derivative Assets And Liabilities Fair Value of Derivatives, Netting Basis (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 147	$ 384
Derivative Liability, Fair Value, Gross Liability	(726)	(788)
Derivative Asset, Fair Value, Amount Offset Against Collateral	(28)	(18)
Derivative Liability, Fair Value, Amount Offset Against Collateral	28	18
Derivative Asset, Collateral, Obligation to Return Cash, Offset	(34)	(318)
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	34	318
Derivative Asset, Fair Value, Net	85	48
Derivative Liability, Fair Value, Net	(664)	(452)
Without offsetting agreements [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	(522)	(399)
OTC Contracts [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	47	41
Derivative Liability, Fair Value, Gross Liability	(45)	(39)
Broker cleared derivative contracts [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	100	343
Derivative Liability, Fair Value, Gross Liability	$ (159)	$ (350)

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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