Leases (Other Information) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 104	$ 102
Operating cash flows from finance leases	6	3
Financing cash flows from finance leases	26	22
Leased assets obtained in exchange for new operating lease liabilities	92	104
Leased assets obtained in exchange for new finance lease liabilities	$ 39	$ 17