Derivatives and Hedging Activities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	$ 176	$ 349
Cash collateral netting	(84)	(63)
Derivative asset and liability netting	(50)	(50)
Total derivatives assets,net	42	236
Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	125	276
Other Assets [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	51	73
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 derivative assets	93	90
Other Assets [Member] | Net Investment Hedging [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	32	186
Accrued Interest And Other Liabilities Member [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative liability	82	53
Cash collateral netting	0	0
Derivative asset and liability netting	(50)	(50)
Total derivatives liabilities, net	32	3
Accrued Interest And Other Liabilities Member [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative liability	18	4
Accrued Interest And Other Liabilities Member [Member] | Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative liability	64	49
Accrued Interest And Other Liabilities Member [Member] | Fair Value Hedging [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative liability	5	4
Accrued Interest And Other Liabilities Member [Member] | Net Investment Hedging [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivative liability	$ 13	$ 0