Leases (Schedule of Lease Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease costs, net	$ 145	$ 132
Variable lease costs	61	70
Short-term lease costs, net	52	59
Amortization of lease assets	14	12
Interest on lease liabilities	5	5
Total lease cost, net	$ 277	$ 278