Derivative Instruments and Hedging Activities (Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Long-term debt	$ 44,193	$ 44,226
Amortized cost basis of the closed portfolios used in hedging relationships	47
Hedged asset, last-of-layer, amount	21,400
Hedge basis adjustment, last-of-layer	19
Carrying amount
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Available-for-sale debt securities	1,485	173
Finance receivables and loans, net	40,850	2,305
Long-term debt	13,001	14,640
Available-for-sale securities
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	0	2
Hedged asset, last-of-layer, amount	28
Hedge basis adjustment, last-of-layer	0
Available-for-sale securities \| Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	(5)	2
Finance receivables and loans, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	24	18
Finance receivables and loans, net \| Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	5	19
Long-term debt
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	67	208
Long-term debt \| Discontinued hedge
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cumulative basis adjustments for fair value hedges included in the carrying amount of hedged items	$ 67	$ 235

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk.

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Amount of asset hedged in last of layer, expected to be remaining at end of hedging relationship.

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Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk, in last-of-layer hedging relationship.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

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Amortized cost of closed portfolio of prepayable financial asset, used to designate hedging relationship in which hedged item is last layer expected to be remaining at end of hedging relationship.

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