Leases (Lease Cost) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Sublease income	$ (157)
Net lease cost	275
Short-term lease, cost	142
Cost of equipment rentals, excluding depreciation
Lessee, Lease, Description [Line Items]
Operating lease cost	370
Selling, general and administrative expenses
Lessee, Lease, Description [Line Items]
Operating lease cost	10
Restructuring charge
Lessee, Lease, Description [Line Items]
Operating lease cost	16
Depreciation of rental equipment
Lessee, Lease, Description [Line Items]
Finance lease cost	28
Non-rental depreciation and amortization
Lessee, Lease, Description [Line Items]
Finance lease cost	2
Interest expense, net
Lessee, Lease, Description [Line Items]
Interest on lease liabilities	$ 6