Leases (Summary of Financial Information Associated with Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Operating lease right-of-use assets	$ 688	$ 669
Total leased assets	913	877
Current
Accrued expenses and other liabilities	178	178
Short-term debt and current maturities of long-term debt	60	58
Long-term
Operating lease liabilities	549	533
Long-term debt	75	69
Total lease liabilities	862	838
Rental equipment, net
Assets
Finance lease, right-of-use asset, before accumulated amortization	295	286
Accumulated depreciation	(86)	(89)
Finance lease, right-of-use asset	209	197
Property and equipment, net
Assets
Accumulated depreciation	(11)	(15)
Finance lease, right-of-use asset	16	11
Non-rental vehicles
Assets
Finance lease, right-of-use asset, before accumulated amortization	8	8
Buildings
Assets
Finance lease, right-of-use asset, before accumulated amortization	$ 19	$ 18