Leases - Other Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 143	$ 160
Financing cash flows from finance leases	2	1
Right-of-use asset operating lease liability	98		$ 170
Right-of-use asset finance lease liability	$ 7	$ 0