Goodwill and Intangible Assets, Net - Balances of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Beginning balance	$ 143	$ 186
Acquisitions	0	0
Dispositions	0	(43)
Impairment and other	0	0
Ending balance	143	143	$ 186
Health Plans
Goodwill [Roll Forward]
Beginning balance	143	143
Acquisitions	0	0
Dispositions	0	0
Impairment and other	0	0	(244)
Ending balance	143	143	143
Other
Goodwill [Roll Forward]
Beginning balance	0	43
Acquisitions	0	0
Dispositions	0	(43)
Impairment and other	0	0	(190)
Ending balance	$ 0	$ 0	$ 43