Leasing Leasing (Schedule of Property Subject to or Available for Operating Lease) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Lessor, Lease, Description [Line Items]
Lease customers enrolling in program	33,000
Percent of lease customers enrolling in program	10.00%
Percent of lease customers electing 120 day deferral	66.00%
Residual value guarantee	15.00%
Vehicles available for operating lease, gross	$ 10,589	$ 10,426
Lessor Operating Lease Accumulated Depreciation	1,525	1,562
Investment in operating leases, net	$ 9,064	8,864
Minimum
Lessor, Lease, Description [Line Items]
Lessor, operating lease, lessee option to purchase underlying asset	P24M
Maximum
Lessor, Lease, Description [Line Items]
Lessor, operating lease, lessee option to purchase underlying asset	P60M
Vehicles
Lessor, Lease, Description [Line Items]
Operating Lease, Residual Value of Leased Asset	$ 386	$ 352