Finance Receivables And Loans, Net Finance Receivables and Loans, Net (Troubled Debt Restructurings) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 885			$ 885
Total TDR movement during the period			151
Financing Receivable, TDRs, Number of Contracts [Line Item]	1,514	1,924		7,445	5,419
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	102	68		449	270
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	87	65		361	252
Loans and Leases Receivable, Impaired, Commitment to Lend	26			26		45
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	1,207	1,629		5,979	4,407
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	14	21		72	58
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	14	21		72	58
First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	218	80		1,140	309
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	74	30		333	111
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	59	29		247	110
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	85	213		312	695
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	5	12		18	39
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	5	11		17	36
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	303	293		1,452	1,004
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	79	42		351	150
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	64	40		264	146
Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	3	0		9	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	7	0		15	3
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	7	0		15	3
Commercial And Industrial Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	0	0		0	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	0	0		0	38
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	0	0		0	28
Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	0	0		0	2
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	0	0		0	11
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	0	0		0	10
Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	1	1		5	2
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	2	2		11	6
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	2	2		10	4
Commercial Real Estate Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	0	1		0	2
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	0	3		0	4
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	0	2		0	3
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	4	2		14	8
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	9	5		26	62
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	$ 9	$ 4		$ 25	$ 48