Lease Commitments Lease Commitments (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Other liabilities and deferred revenue, current	$ 309	$ 0
Other liabilities and deferred revenue, non-current	958	$ 0
Total operating lease liabilities	1,267
Accumulated depreciation	40
Total finance lease liabilities	156
Other Noncurrent Assets
Lessee, Lease, Description [Line Items]
Other assets, non-current	1,264
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Other liabilities and deferred revenue, current	309
Other Noncurrent Liabilities
Lessee, Lease, Description [Line Items]
Other liabilities and deferred revenue, non-current	958
Property, Plant and Equipment
Lessee, Lease, Description [Line Items]
Property and equipment, gross	227
Property and equipment, net	187
Debt | Operating Segments | Automotive
Lessee, Lease, Description [Line Items]
Automotive debt payable within one year	88
Automotive long-term debt	$ 68
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	40 years