Derivative Instruments (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Asset and liability management derivative positions of the company
Notional Value	$ 36,000
Derivative Financial Instruments, Assets [Member] | Fair value hedges [Member] | Foreign exchange cross-currency swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	1,452	891
Fair Value, Assets	144	70
Weighted - Average Remaining Maturity In Years	5.75	6.17
Derivative Financial Instruments, Assets [Member] | Fair value hedges [Member] | Interest rate contracts [Member] | Receive fixed/pay floating swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	1,800	1,800
Fair Value, Assets	46	72
Weighted - Average Remaining Maturity In Years	41.88	55.75
Derivative Financial Instruments, Assets [Member] | Cash flow hedges [Member] | Interest rate contracts [Member] | Pay fixed/receive floating swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	0	0
Fair Value, Assets	0	0
Weighted - Average Remaining Maturity In Years	0	0
Derivative Financial Instruments, Assets [Member] | Net investment hedges [Member] | Foreign exchange forward contracts [Member]
Asset and liability management derivative positions of the company
Notional Value	0	512
Fair Value, Assets	0	3
Weighted - Average Remaining Maturity In Years	0	0.08
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Credit Risk Contract [Member]
Asset and liability management derivative positions of the company
Notional Value	551	650
Fair Value, Assets	1	2
Weighted - Average Remaining Maturity In Years	2.43	3.22
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Equity Contract [Member]
Asset and liability management derivative positions of the company
Notional Value	32	61
Fair Value, Assets	2	3
Weighted - Average Remaining Maturity In Years	1.79	1.60
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Futures and Forwards Buy [Member]
Asset and liability management derivative positions of the company
Notional Value	2,573	2,879
Fair Value, Assets	13	20
Weighted - Average Remaining Maturity In Years	0.11	0.10
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Futures and Forwards Sell [Member]
Asset and liability management derivative positions of the company
Notional Value	3,438	9,082
Fair Value, Assets	16	207
Weighted - Average Remaining Maturity In Years	0.16	0.07
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Receive fixed/pay floating swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	400	2,250
Fair Value, Assets	1	3
Weighted - Average Remaining Maturity In Years	10.36	10.22
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Purchased Option [Member]
Asset and liability management derivative positions of the company
Notional Value	4,250	1,600
Fair Value, Assets	0	0
Weighted - Average Remaining Maturity In Years	0.06	0.06
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Written Option [Member]
Asset and liability management derivative positions of the company
Notional Value	3,723	6,321
Fair Value, Assets	18	23
Weighted - Average Remaining Maturity In Years	0.07	0.07
Derivative Financial Instruments, Assets [Member] | Other economic hedges [Member] | Foreign exchange forward contracts [Member]
Asset and liability management derivative positions of the company
Notional Value	150	158
Fair Value, Assets	1	1
Weighted - Average Remaining Maturity In Years	0.10	0.09
Derivative Financial Instruments, Liabilities [Member] | Fair value hedges [Member] | Foreign exchange cross-currency swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	0	445
Fair Value, Liabilities	0	0
Weighted - Average Remaining Maturity In Years	0	6.17
Derivative Financial Instruments, Liabilities [Member] | Fair value hedges [Member] | Interest rate contracts [Member] | Receive fixed/pay floating swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	0	0
Fair Value, Liabilities	0	0
Weighted - Average Remaining Maturity In Years	0	0
Derivative Financial Instruments, Liabilities [Member] | Cash flow hedges [Member] | Interest rate contracts [Member] | Pay fixed/receive floating swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	4,788	4,788
Fair Value, Liabilities	705	688
Weighted - Average Remaining Maturity In Years	4.60	5.03
Derivative Financial Instruments, Liabilities [Member] | Net investment hedges [Member] | Foreign exchange forward contracts [Member]
Asset and liability management derivative positions of the company
Notional Value	561	0
Fair Value, Liabilities	0	0
Weighted - Average Remaining Maturity In Years	0.08	0
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Credit Risk Contract [Member]
Asset and liability management derivative positions of the company
Notional Value	1,471	1,183
Fair Value, Liabilities	8	7
Weighted - Average Remaining Maturity In Years	2.83	2.71
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Equity Contract [Member]
Asset and liability management derivative positions of the company
Notional Value	29	0
Fair Value, Liabilities	1	0
Weighted - Average Remaining Maturity In Years	0.08	0
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Futures and Forwards Buy [Member]
Asset and liability management derivative positions of the company
Notional Value	3,890	6,312
Fair Value, Liabilities	19	79
Weighted - Average Remaining Maturity In Years	0.07	0.05
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Futures and Forwards Sell [Member]
Asset and liability management derivative positions of the company
Notional Value	3,127	6,002
Fair Value, Liabilities	34	51
Weighted - Average Remaining Maturity In Years	0.08	0.09
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Receive fixed/pay floating swaps [Member]
Asset and liability management derivative positions of the company
Notional Value	2,875	0
Fair Value, Liabilities	40	0
Weighted - Average Remaining Maturity In Years	10.36	0
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Purchased Option [Member]
Asset and liability management derivative positions of the company
Notional Value	0	0
Fair Value, Liabilities	0	0
Weighted - Average Remaining Maturity In Years	0	0
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Interest rate contracts [Member] | Written Option [Member]
Asset and liability management derivative positions of the company
Notional Value	131	1,348
Fair Value, Liabilities	0	9
Weighted - Average Remaining Maturity In Years	0.10	0.07
Derivative Financial Instruments, Liabilities [Member] | Other economic hedges [Member] | Foreign exchange forward contracts [Member]
Asset and liability management derivative positions of the company
Notional Value	775	694
Fair Value, Liabilities	$ 6	$ 6
Weighted - Average Remaining Maturity In Years	0.09	0.09