Fair Value (Fair Value Measurements - Reconciliation of Level 3 Assets And Liabilities) (Details) - Fair value, measurements, recurring - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Derivative liabilities, net of derivative assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, transfers into level 3	$ 0	$ 0
Fair value, measurement, recurring, transfers out of level 3	0	0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value, Beginning Balance	12	(2)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	15	(6)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances	1	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value	28	(8)
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss)	15	(6)
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Equity securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	7	8
Fair value, measurement, recurring, asset, gain (loss) included in earnings	4	(4)
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	0	0
Fair value, measurement, recurring, asset, sales	0	0
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	0
Fair value, measurement, recurring, transfers into level 3	0	0
Fair value, measurement, recurring, transfers out of level 3	0	0
Fair value, measurement, recurring, asset value, ending balance	11	4
Fair value, assets, recurring, net unrealized gains (losses)	4	(4)
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	7	2
Fair value, measurement, recurring, asset, gain (loss) included in earnings	0	0
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	0	1
Fair value, measurement, recurring, asset, sales	0	0
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	0
Fair value, measurement, recurring, transfers into level 3	0	0
Fair value, measurement, recurring, transfers out of level 3	0	0
Fair value, measurement, recurring, asset value, ending balance	7	3
Fair value, assets, recurring, net unrealized gains (losses)	0	0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Loans held-for-sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	91	30
Fair value, measurement, recurring, asset, gain (loss) included in earnings	28	5
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	1,039	302
Fair value, measurement, recurring, asset, sales	(1,012)	(269)
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	0
Fair value, measurement, recurring, transfers into level 3	0	0
Fair value, measurement, recurring, transfers out of level 3	0	0
Fair value, measurement, recurring, asset value, ending balance	146	68
Fair value, assets, recurring, net unrealized gains (losses)	1	1
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Finance receivables and Loans, net | Consumer Loan
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	8	11
Fair value, measurement, recurring, asset, gain (loss) included in earnings	2	(1)
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	4	6
Fair value, measurement, recurring, asset, sales	0	0
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	(6)	(6)
Fair value, measurement, recurring, transfers into level 3	0	0
Fair value, measurement, recurring, transfers out of level 3	0	0
Fair value, measurement, recurring, asset value, ending balance	8	10
Fair value, assets, recurring, net unrealized gains (losses)	0	0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Interests retained in financial asset sales
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, measurement, recurring, asset value, beginning balance	0	2
Fair value, measurement, recurring, asset, gain (loss) included in earnings	0	0
Fair value, measurement, recurring, asset, gain (loss) included in other comprehensive income (loss)	0	0
Fair value, measurement, recurring, asset, purchases	0	0
Fair value, measurement, recurring, asset, sales	0	0
Fair value, measurement , recurring, asset, issuances	0	0
Fair value, measurement, recurring, asset, settlements	0	(1)
Fair value, measurement, recurring, transfers into level 3	0	0
Fair value, measurement, recurring, transfers out of level 3	0	0
Fair value, measurement, recurring, asset value, ending balance	0	1
Fair value, assets, recurring, net unrealized gains (losses)	0	0
Fair value, assets measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	0	0
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair value, liabilities measured on recurring basis, change in unrealized gain (loss) included in other comprehensive income	$ 0	$ 0