Allowance for Credit Losses (Schedule of Information Regarding Impaired Loans) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2012		Dec. 31, 2011
Related Allowance	$ 2,126		$ 2,256
Government Guaranteed Loans [Member]
Recorded Investment	264		232
Related Allowance	13		27
Impaired Loans Excluding Acquired Impaired [Member]
Recorded Investment	2,419	[1]	2,577	[1]
Unpaid Principal Balance	2,876	[1]	3,048	[1]
Related Allowance	357	[1]	405	[1]
Average Recorded Investment	2,064	[1]	1,958	[1]
Interest Income Recognized	24	[1]	50	[1]
With No Related Allowance Recorded [Member] | Commercial and Industrial [Member]
Recorded Investment	129		114
Unpaid Principal Balance	236		196
Average Recorded Investment	122		102
Interest Income Recognized	0		0
With No Related Allowance Recorded [Member] | Commercial Real Estate - Other [Member]
Recorded Investment	78		102
Unpaid Principal Balance	122		163
Average Recorded Investment	67		94
Interest Income Recognized	0		1
With No Related Allowance Recorded [Member] | Commercial Real Estate - Residential ADC [Member]
Recorded Investment	107		153
Unpaid Principal Balance	227		289
Average Recorded Investment	125		145
Interest Income Recognized	0		0
With No Related Allowance Recorded [Member] | Direct Retail Lending [Member]
Recorded Investment	18		19
Unpaid Principal Balance	75		74
Average Recorded Investment	20		23
Interest Income Recognized	0		1
With No Related Allowance Recorded [Member] | Retail Residential Mortgage [Member]
Recorded Investment	82	[1]	46	[1]
Unpaid Principal Balance	138	[1]	85	[1]
Average Recorded Investment	101	[1]	55	[1]
Interest Income Recognized	1	[1]	2	[1]
With No Related Allowance Recorded [Member] | Retail Sales Finance [Member]
Recorded Investment	2		1
Unpaid Principal Balance	2		1
Average Recorded Investment	1		1
Interest Income Recognized	0		0
With No Related Allowance Recorded [Member] | Retail Other Lending Subsidiaries [Member]
Recorded Investment	2		2
Unpaid Principal Balance	4		4
Average Recorded Investment	4		3
Interest Income Recognized	0		0
With An Allowance Recorded [Member] | Commercial and Industrial [Member]
Recorded Investment	562		542
Unpaid Principal Balance	571		552
Related Allowance	83		77
Average Recorded Investment	395		300
Interest Income Recognized	1		1
With An Allowance Recorded [Member] | Commercial Real Estate - Other [Member]
Recorded Investment	335		409
Unpaid Principal Balance	357		433
Related Allowance	47		69
Average Recorded Investment	240		278
Interest Income Recognized	2		5
With An Allowance Recorded [Member] | Commercial Real Estate - Residential ADC [Member]
Recorded Investment	165		267
Unpaid Principal Balance	172		298
Related Allowance	28		50
Average Recorded Investment	121		164
Interest Income Recognized	0		1
With An Allowance Recorded [Member] | Commercial Other Lending Subsidiaries [Member]
Recorded Investment	8		5
Unpaid Principal Balance	8		5
Related Allowance	2		1
Average Recorded Investment	2		5
Interest Income Recognized	1		0
With An Allowance Recorded [Member] | Direct Retail Lending [Member]
Recorded Investment	136		146
Unpaid Principal Balance	145		153
Related Allowance	28		35
Average Recorded Investment	130		128
Interest Income Recognized	4		8
With An Allowance Recorded [Member] | Retail Revolving Credit [Member]
Recorded Investment	58		62
Unpaid Principal Balance	58		61
Related Allowance	25		27
Average Recorded Investment	60		61
Interest Income Recognized	1		3
With An Allowance Recorded [Member] | Retail Residential Mortgage [Member]
Recorded Investment	652	[1]	653	[1]
Unpaid Principal Balance	672	[1]	674	[1]
Related Allowance	114	[1]	125	[1]
Average Recorded Investment	616	[1]	562	[1]
Interest Income Recognized	13	[1]	26	[1]
With An Allowance Recorded [Member] | Retail Sales Finance [Member]
Recorded Investment	15		9
Unpaid Principal Balance	17		10
Related Allowance	3		1
Average Recorded Investment	9		6
Interest Income Recognized	0		0
With An Allowance Recorded [Member] | Retail Other Lending Subsidiaries [Member]
Recorded Investment	70		47
Unpaid Principal Balance	72		50
Related Allowance	27		20
Average Recorded Investment	51		31
Interest Income Recognized	$ 1		$ 2

[1] Residential mortgage loans exclude $264 million and $232 million in government guaranteed loans and related allowance of $13 million and $27 million as of June 30, 2012 and December 31, 2011, respectively.