Lease Commitments - Schedule of Operating and Finance Lease Maturities (Details) $ in Millions	Mar. 31, 2020 USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	$ 382
2021	386
2022	136
2023	102
2024	81
Thereafter	248
Total lease payments	1,335
Less: Interest	(114)
Total lease liabilities	1,221
Remainder of 2020
Finance Lease, Liability, Payments, Remainder of Fiscal Year	31
2021	37
2022	34
2023	32
2024	30
Thereafter	261
Total lease payments	425
Less: Interest	(79)
Total lease liabilities	346
Operating and Finance Lease Liabilities, Payments, Due [Abstract]
Remainder of 2020	413
2021	423
2022	170
2023	134
2024	111
Thereafter	509
Total lease payments	1,760
Less: Interest	(193)
Total lease liabilities	$ 1,567
Weighted average lease term, operating lease	4 years 9 months 18 days
Weighted average discount rate, operating lease	2.85%
Weighted average lease term, finance lease	11 years 9 months 18 days
Weighted average discount rate, finance lease	3.39%