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
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 829		$ 829
Total TDR movement during the period			95
Financing Receivable, TDRs, Number of Contracts [Line Item]	2,885	1,923	5,931	3,495
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	271	125	347	202
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	200	112	274	187
Loans and Leases Receivable, Impaired, Commitment to Lend	29		29		45
Consumer Loans Auto Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	1,980	1,550	4,772	2,778
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	25	20	58	37
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	25	20	58	37
First Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	845	102	922	229
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	231	37	259	81
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	161	37	188	81
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	54	266	227	482
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	3	14	13	27
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	3	14	12	25
Residential Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	899	368	1,149	711
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	234	51	272	108
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	164	51	200	106
Commercial And Industrial Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	3	0	6	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	5	0	8	3
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	5	0	8	3
Commercial And Industrial Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	0	1	0	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	0	38	0	38
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	0	28	0	28
Commercial And Industrial Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	0	2	0	2
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	0	11	0	11
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	0	10	0	10
Commercial Real Estate Automobile [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	3	1	4	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	7	4	9	4
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	6	2	8	2
Commercial Real Estate Mortgage [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	0	1	0	1
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	0	1	0	1
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	0	1	0	1
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, TDRs, Number of Contracts [Line Item]	6	5	10	6
Financing Receivable, TDRs, Pre-Modification Recorded Investment [Line Item]	12	54	17	57
Financing Receivable, TDRs, Post-Modification Recorded Investment [Line Item]	$ 11	$ 41	$ 16	$ 44