Leases (Other Information) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 156	$ 151
Operating cash flows from finance leases	9	5
Financing cash flows from finance leases	39	35
Leased assets obtained in exchange for new operating lease liabilities	135	147
Leased assets obtained in exchange for new finance lease liabilities	$ 54	$ 36