Goodwill and Intangible Assets, Net - Intangible Assets Balances (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Cost	$ 199	$ 221
Accumulated Amortization	170	174
Carrying Amount	29	47
Contract rights and licenses
Finite-Lived Intangible Assets [Line Items]
Cost	179	201
Accumulated Amortization	156	162
Carrying Amount	23	39
Provider networks
Finite-Lived Intangible Assets [Line Items]
Cost	20	20
Accumulated Amortization	14	12
Carrying Amount	$ 6	$ 8