Selected Quarterly Financial Data (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2020	Sep. 30, 2020
Quarterly Financial Information Disclosure [Abstract]
Impairment charge adjustment	[1]	$ 8	$ 8
Adjustment for asset reclassification			(26)
Net cash provided by (used in) operating activities, continuing operations, previously reported			(11)
Net cash provided by (used in) operating activities, discontinued operations, previously reported			(1)
Insurance premium classification adjustment			(13)
Net cash provided by (used in) financing activities, previously reported			7
Net cash provided by (used in) operating activities, previously reported			(12)
Other assets, reclassification			$ 13

[1] The $8 adjustment summarized above impacts the “Asset impairments” caption within the financial results table in the Discontinued Operations footnote. The adjustment also impacts “Comprehensive loss” and “Accumulated deficit.”