Derivatives and Hedging Activities (Details 7) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	$ 2,082,143,000,000	$ 2,046,763,000,000
Maximum Payout/Notional Amount of Purchased Credit Derivatives	2,220,000,000,000	2,190,000,000,000
Fair Value Asset of Written Credit Derivatives	40,105,000,000	42,493,000,000
Fair Value Liability of Written Credit Derivatives	64,552,000,000	67,445,000,000
Fair Value Net Asset/(Liability) of Written Credit Derivatives	(24,447,000,000)	(24,952,000,000)
Net purchased protection notional value of credit derivatives	140,510,000,000	140,630,000,000
Offsetting Purchased Credit Derivatives [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	1,900,624,000,000	1,875,690,000,000
Offsetting Purchased Credit Derivatives [Member] | 0-250 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	1,544,169,000,000	1,511,113,000,000
Offsetting Purchased Credit Derivatives [Member] | 251-500 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	177,754,000,000	183,613,000,000
Offsetting Purchased Credit Derivatives [Member] | 501-1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	103,322,000,000	110,019,000,000
Offsetting Purchased Credit Derivatives [Member] | Greater than 1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	75,379,000,000	70,945,000,000
Other Purchased Credit Derivatives [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	322,027,000,000	311,700,000,000
Other Purchased Credit Derivatives [Member] | 0-250 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	250,334,000,000	232,506,000,000
Other Purchased Credit Derivatives [Member] | 251-500 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	34,221,000,000	36,713,000,000
Other Purchased Credit Derivatives [Member] | 501-1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	18,577,000,000	18,686,000,000
Other Purchased Credit Derivatives [Member] | Greater than 1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Purchased Credit Derivatives	18,895,000,000	23,795,000,000
0-12 Months [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	316,267,000,000	268,315,000,000
0-12 Months [Member] | 0-250 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	280,294,000,000	235,798,000,000
0-12 Months [Member] | 251-500 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	14,348,000,000	14,412,000,000
0-12 Months [Member] | 501-1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	11,066,000,000	6,384,000,000
0-12 Months [Member] | Greater than 1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	10,559,000,000	11,721,000,000
1-5 Years [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	1,412,143,000,000	1,391,950,000,000
1-5 Years [Member] | 0-250 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	1,114,921,000,000	1,094,308,000,000
1-5 Years [Member] | 251-500 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	148,516,000,000	144,448,000,000
1-5 Years [Member] | 501-1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	85,855,000,000	89,212,000,000
1-5 Years [Member] | Greater than 1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	62,851,000,000	63,982,000,000
5 Years or Greater [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	353,733,000,000	386,498,000,000
5 Years or Greater [Member] | 0-250 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	261,840,000,000	288,851,000,000
5 Years or Greater [Member] | 251-500 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	50,168,000,000	52,072,000,000
5 Years or Greater [Member] | 501-1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	26,656,000,000	33,553,000,000
5 Years or Greater [Member] | Greater than 1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	15,069,000,000	12,022,000,000
0-250 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	1,657,055,000,000	1,618,957,000,000
Fair Value Asset of Written Credit Derivatives	29,771,000,000	32,071,000,000
Fair Value Liability of Written Credit Derivatives	12,915,000,000	14,780,000,000
Fair Value Net Asset/(Liability) of Written Credit Derivatives	16,856,000,000	17,291,000,000
251-500 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	213,032,000,000	210,932,000,000
Fair Value Asset of Written Credit Derivatives	7,097,000,000	7,368,000,000
Fair Value Liability of Written Credit Derivatives	6,248,000,000	7,739,000,000
Fair Value Net Asset/(Liability) of Written Credit Derivatives	849,000,000	(371,000,000)
501-1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	123,577,000,000	129,149,000,000
Fair Value Asset of Written Credit Derivatives	2,868,000,000	2,571,000,000
Fair Value Liability of Written Credit Derivatives	10,122,000,000	11,256,000,000
Fair Value Net Asset/(Liability) of Written Credit Derivatives	(7,254,000,000)	(8,685,000,000)
Greater than 1000 [Member]
Summary of Credit Derivatives [Abstract]
Maximum Payout/Notional Amount of Written Credit Derivatives	88,479,000,000	87,725,000,000
Fair Value Asset of Written Credit Derivatives	369,000,000	483,000,000
Fair Value Liability of Written Credit Derivatives	35,267,000,000	33,670,000,000
Fair Value Net Asset/(Liability) of Written Credit Derivatives	$ (34,898,000,000)	$ (33,187,000,000)