Derivative Instruments and Hedging Activities (Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Closed Portfolio and Beneficial Interest, Last-of-Layer, Amortized Cost	$ 597	$ 230
Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset, Fair Value Hedge	1,270	1,217
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	50	18
Hedged asset, last-of-layer, amount	490	0
Hedge basis adjustment, last-of-layer	3
Finance receivables and Loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset, Fair Value Hedge	36,211	33,312
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease)	334	135
Hedged asset, last-of-layer, amount	10,200	10,200
Hedge basis adjustment, last-of-layer	255	91
Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Liability, Fair Value Hedge	10,020	11,995
Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease)	196	24
Discontinued hedge | Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	32	18
Hedged asset, last-of-layer, amount	690	200
Hedge basis adjustment, last-of-layer	22	2
Discontinued hedge | Finance receivables and Loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Asset, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	79	44
Hedged asset, last-of-layer, amount	17,500	12,800
Hedge basis adjustment, last-of-layer	79	43
Discontinued hedge | Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease)	$ 196	$ 127