Guarantee Arrangements and Pledged Assets (Details Textual) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended	24 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2012	Mar. 31, 2011
Guarantee Arrangements Pledged Asset and Regulatory matters (Textual) [Abstract]
Outstanding financial standby letters of credit	$ 5,000,000,000		$ 5,000,000,000		$ 4,700,000,000
Outstanding financial standby performance guarantees	2,900,000,000		2,900,000,000		3,100,000,000
Deferred fee on stand by letters of credit	52,000,000		52,000,000		44,000,000
Allowance for credit losses on unfunded standby letters of credit	24,000,000		24,000,000		22,000,000
Principal amount outstanding on loans sold to government sponsored entities	17,200,000,000		17,200,000,000		19,300,000,000
Principal amount outstanding on loans from our legacy broker channel	11,000,000,000		11,000,000,000		12,100,000,000
Repurchase demands received from our legacy broker channel	151,000,000	75,000,000
Repurchase demands on loans sourced from our legacy broker channel			233,000,000	157,000,000
Outstanding repurchase demands on loans sourced from our legacy broker channel	138,000,000		138,000,000		87,000,000
Mortgage repurchase liability	222,000,000	237,000,000	222,000,000	237,000,000	237,000,000	262,000,000	223,000,000	270,000,000
Liquidity facilities	3,211,000,000	2,470,000,000	3,211,000,000	2,470,000,000
Liquidity facilities	1,100,000,000		1,100,000,000		677,000,000
Escrow account to fund future claims	3,000,000,000		3,000,000,000
Increased escrow account to fund future claims	4,100,000,000		4,100,000,000
Additional escrow account					2,000,000,000
Reduction in contingent liability						24,000,000
Maximum time to resolve case			12 months
Minimum time to resolve case			3 months
Reduction in litigation liabilities					9,000,000
Net contingent liabilities	0		0
Credit derivatives [Member]
Guarantor Obligations [Line Items]
Guarantee Arrangement for the benefit of Affiliates	48,000,000,000		48,000,000,000		45,100,000,000
Financial standby letters of credit, net of participations [Member]
Guarantor Obligations [Line Items]
Guarantee Arrangement for the benefit of Affiliates	$ 652,000,000		$ 652,000,000		$ 707,000,000