Leases - Additional information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Amortization of ROU assets	$ 9	$ 8
Interest on lease liability	1	2
Finance lease cost	10	10
Operating lease cost	17	26
Short-term lease cost	32	112
Total lease cost	59	148
Other information:
Operating cash outflows from finance lease	1	2
Operating cash outflows from operating leases	9	11
Investing cash outflows from operating leases	40	127
Financing cash outflows from finance lease	$ 9	$ 8
Weighted average remaining lease term - finance lease	1 year	2 years
Weighted average remaining lease term - operating leases	1 year 1 month 13 days	4 years 7 months 24 days
Weighted average discount rate - finance lease	7.50%	7.50%
Weighted average discount rate - operating leases	6.46%	4.85%