Lease Commitments - Cash Flow of Lessee (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows for operating leases	$ 244	$ 236
Financing cash flows for finance leases	23	12
Non-cash related activities
ROU assets obtained in exchange for new operating lease liabilities	44	146
ROU assets obtained in exchange for new finance lease liabilities	0	13
Operating lease ROU asset expense	142	178
Changes in Non-current operating lease liabilities	$ (125)	$ (47)