Derivatives and Hedging Activities (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Not Sold Or Repledged [Member]
Derivatives, Fair Value [Line Items]
Securities received as collateral	$ 0	$ 335
Risk Exposure Low [Member]
Derivatives, Fair Value [Line Items]
Total derivatives, net	587	258
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	1,028	942
Cash collateral netting	(406)	(326)
Derivative asset and liability netting	(35)	(23)
Total derivatives, net	587	593
Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	937	867
Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	91	75
Other Assets [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	0	0
Other Assets [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	91	75
Other Assets [Member] | Equity-linked contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	0	0
Other Assets [Member] | Fair Value Hedging [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	528	824
Other Assets [Member] | Fair Value Hedging [Member] | Total Return Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	20	0
Other Assets [Member] | Net Investment Hedging [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	389	43
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	150	329
Cash collateral netting	0	(21)
Derivative asset and liability netting	(35)	(23)
Total derivatives, net	115	285
Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	36	169
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	114	160
Other Liabilities [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	0	0
Other Liabilities [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	114	158
Other Liabilities [Member] | Equity-linked contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	0	2
Other Liabilities [Member] | Fair Value Hedging [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	0	0
Other Liabilities [Member] | Fair Value Hedging [Member] | Total Return Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	0	19
Other Liabilities [Member] | Net Investment Hedging [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	$ 36	$ 150