Debt and Commitments - Asset Backed Debt (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Asset Backed Debt [Abstract]
Cash and cash equivalents	$ 15,659,000,000	$ 17,148,000,000	$ 14,805,000,000	$ 20,894,000,000
Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	9,412,000,000	9,183,000,000	8,504,000,000	11,132,000,000
Variable Interest Entity, Primary Beneficiary [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	2,911,000,000	3,402,000,000
Variable Interest Entity, Primary Beneficiary [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	2,900,000,000	3,400,000,000
Finance Receivables Net And Net Investment In Operating Leases	53,800,000,000	56,200,000,000
Long-term Debt, Gross	40,200,000,000	41,400,000,000
Variable Interest Entities Liabilities Excluded	145,000,000	246,000,000
Finance Receivables [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	100,000,000	300,000,000
Finance Receivables Net And Net Investment In Operating Leases	3,500,000,000	6,200,000,000
Long-term Debt, Gross	3,300,000,000	5,600,000,000
Finance Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	2,500,000,000	3,000,000,000
Finance Receivables Net And Net Investment In Operating Leases	47,500,000,000	49,800,000,000
Long-term Debt, Gross	36,000,000,000	37,200,000,000
Net Investment in Operating Leases [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	400,000,000	400,000,000
Finance Receivables Net And Net Investment In Operating Leases	6,300,000,000	6,400,000,000
Long-term Debt, Gross	4,200,000,000	4,200,000,000
Net Investment in Operating Leases [Member] | Variable Interest Entity, Primary Beneficiary [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	400,000,000	400,000,000
Finance Receivables Net And Net Investment In Operating Leases	6,300,000,000	6,400,000,000
Securitization Transactions [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	3,000,000,000	3,700,000,000
Finance Receivables Net And Net Investment In Operating Leases	57,300,000,000	62,400,000,000
Long-term Debt, Gross	43,500,000,000	47,000,000,000
Securitization Transactions [Member] | Finance Receivables [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	2,600,000,000	3,300,000,000
Finance Receivables Net And Net Investment In Operating Leases	51,000,000,000	56,000,000,000
Long-term Debt, Gross	39,300,000,000	42,800,000,000
Securitization Transactions [Member] | Net Investment in Operating Leases [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Cash and cash equivalents	400,000,000	400,000,000
Finance Receivables Net And Net Investment In Operating Leases	6,300,000,000	6,400,000,000
Long-term Debt, Gross	4,200,000,000	4,200,000,000
Asset backed-debt [Member] | Securities Pledged as Collateral [Member] | Financial Services [Member]
Asset Backed Debt [Abstract]
Secured Debt	$ 64,000,000	$ 75,000,000