Derivatives and Hedging Activities (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	$ 662	$ 942
Total fair value of derivatives liabilties	275	329
Not Sold Or Repledged [Member]
Derivative [Line Items]
Securities received as collateral	0	335
Risk Exposure Low [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets, net	255	258
Derivative [Line Items]
Total derivative assets, net	255	258
Individually Significant Counterparties [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets, net	0	0
Total derivative liabilities, net	0	0
Derivative [Line Items]
Total derivative assets, net	0	0
Total derivative liabilities, net	0	0
Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	0	0
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Cash collateral netting	(380)	(326)
Derivative asset and liability netting	(27)	(23)
Total derivative assets, net	255	593
Derivative [Line Items]
Total derivative assets, net	255	593
Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	566	867
Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	96	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	96	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	517	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	0	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	49	43
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Cash collateral netting	(14)	(21)
Derivative asset and liability netting	(27)	(23)
Total derivative liabilities, net	234	285
Derivative [Line Items]
Total derivative liabilities, net	234	285
Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	170	169
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	105	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	105	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	6	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	$ 164	$ 150