Fair Value FV Realized and Unrealized Gains and Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total realized and unrealized gains (losses) included in net income	$ 266	$ 141	$ 549	$ (25)
Net unrealized gains (losses) related to Level 3 assets and liabilities still held	97	99	331	94
Interest Income [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total realized and unrealized gains (losses) included in net income	62	60	187	205
Net unrealized gains (losses) related to Level 3 assets and liabilities still held	0	0	0	0
Fair Value Gains (Losses), Net [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total realized and unrealized gains (losses) included in net income	181	117	342	237
Net unrealized gains (losses) related to Level 3 assets and liabilities still held	97	99	331	94
Net Other-than-Temporary Impairments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total realized and unrealized gains (losses) included in net income	(11)	(37)	(20)	(476)
Net unrealized gains (losses) related to Level 3 assets and liabilities still held	0	0	0	0
Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total realized and unrealized gains (losses) included in net income	34	1	40	9
Net unrealized gains (losses) related to Level 3 assets and liabilities still held	$ 0	$ 0	$ 0	$ 0