Leasing (Depreciation Expense on Operating Lease Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease revenue	$ 1,550	$ 1,435	$ 1,470
Depreciation expense on operating lease assets	914	978	1,050
Remarketing gains, net	(344)	(127)	(69)
Net depreciation expense on operating lease assets	570	851	981
Variable lease payments, excessive wear and tear	$ 16	$ 23	$ 19