Goodwill and Other Intangible Assets - Summary of Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill
Gross Carrying Amount	$ 289	$ 289
Net Carrying Amount	289	289
Amortizable intangibles:
Gross Carrying Amount	95	95
Accumulated Amortization	(80)	(74)
Net Carrying Amount	15	21
Amortization of intangible assets	$ 5	5	$ 5
Customer contracts
Amortizable intangibles:
Weighted Average Amortization Period	10 years
Gross Carrying Amount	$ 90	90
Accumulated Amortization	(76)	(71)
Net Carrying Amount	$ 14	19
Developed technology
Amortizable intangibles:
Weighted Average Amortization Period	5 years
Gross Carrying Amount	$ 5	5
Accumulated Amortization	(4)	(3)
Net Carrying Amount	$ 1	$ 2