Derivative Instruments and Other Financial Instruments Used For Hedging - Schedule of Derivative Gains (Losses) on the Company's Fair Value Hedges (Details) - Fair value hedges - Interest rate derivative contracts - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018
Amount and location of net gains and losses
Derivative	$ 0	$ (2)
Hedged Item	0	2
Hedge Ineffectiveness	0	0
Designated as Hedging Instrument
Amount and location of net gains and losses
Derivative	0	(2)
Hedged Item	0	2
Hedge Ineffectiveness	$ 0	$ 0