Leases (Summary of Financial Information Associated with Leases) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Assets
Operating lease right-of-use assets	$ 622	$ 0
Total leased assets	803
Current
Accrued expenses and other liabilities	169
Short-term debt and current maturities of long-term debt	39
Long-term
Operating lease liabilities	497	$ 0
Long-term debt	80
Total lease liabilities	785
Rental equipment
Assets
Finance lease assets, gross	263
Less accumulated depreciation and amortization	(87)
Finance lease assets, net	176
Property and equipment, net
Assets
Less accumulated depreciation and amortization	(18)
Finance lease assets, net	5
Non-rental vehicles
Assets
Finance lease assets, gross	7
Buildings
Assets
Finance lease assets, gross	$ 16