Derivatives and Hedging Activities (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	$ 151,000,000	$ 210,000,000
Total fair value of derivatives liabilties	379,000,000	218,000,000
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Cash collateral netting	0	6,000,000
Derivative asset and liability netting	(85,000,000)	(80,000,000)
Total derivative assets	66,000,000	124,000,000
Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	74,000,000	128,000,000
Other Assets [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives assets	77,000,000	82,000,000
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	3,000,000	11,000,000
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	71,000,000	117,000,000
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Cash collateral netting	(94,000,000)	(45,000,000)
Derivative asset and liability netting	(85,000,000)	(80,000,000)
Total derivative liabilities	200,000,000	93,000,000
Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	262,000,000	123,000,000
Other Liabilities [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total fair value of derivatives liabilties	117,000,000	95,000,000
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	95,000,000	34,000,000
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	$ 167,000,000	89,000,000
Individually Significant Counterparties [Member]
Derivatives, Fair Value [Line Items]
Total derivative assets		0
Total derivative liabilities		$ 0