Finance Receivables - Maturities and Investments in Direct Financing Leases (Details) (Consumer Portfolio Segment [Member], Retail [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Finance Receivables Maturity [Abstract]
Finance receivables before unearned interest supplements	$ 48,138	$ 48,468
Investment in Direct Financing Leases [Abstract]
Less: Unearned interest supplements	(1,385)	(1,486)
North America Segment [Member]
Finance Receivables Maturity [Abstract]
Finance receivables before unearned interest supplements	39,369	39,504
Investment in Direct Financing Leases [Abstract]
Less: Unearned interest supplements	(1,172)	(1,264)
International Segment [Member]
Finance Receivables Maturity [Abstract]
Finance receivables before unearned interest supplements	8,769	8,964
Investment in Direct Financing Leases [Abstract]
Less: Unearned interest supplements	$ (213)	$ (222)