Derivative Instruments and Hedging Activity - Additional Disclosures (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount	$ 3,419		$ 3,419		$ 2,119
Net losses included in AOCI expected to be reclassified into interest expense within the next 12 months	6		6
Foreign Currency Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Notional amount	58		58		$ 46
Losses related to foreign currency contract	2	$ 1	5	$ 2
Credit Risk Related Contingent Contracts [Member]
Derivative [Line Items]
Fair value of derivative instruments, liabilities	$ 7		$ 7