Derivatives and Hedging Activities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Total fair value of derivative assets	$ 514	$ 210
Total fair value of derivative liabilities	214	218
Total derivatives assets, net	396	124
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative asset and liability netting	(90)	(80)
Total derivatives assets, net	396	124
Cash collateral netting, Assets	(28)	(6)
Other Assets [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	256	128
Other Assets [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	514	210
Other Assets [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	34	11
Other Assets [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	222	117
Other Assets [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives assets, net	258	82
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative asset and liability netting	(90)	(80)
Total derivatives liabilities, net	46	93
Cash collateral netting, Liabilities	(78)	(45)
Other Liabilities [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives liabilities, net	135	123
Other Liabilities [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives liabilities, net	214	218
Other Liabilities [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives liabilities, net	74	34
Other Liabilities [Member] | Foreign exchange contracts [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives liabilities, net	61	89
Other Liabilities [Member] | Foreign exchange contracts [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Total derivatives liabilities, net	$ 79	$ 95