Lease Commitments - Schedule of Operating and Finance Lease Maturities (Details) $ in Millions	Sep. 30, 2020 USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	$ 117
2021	454
2022	182
2023	110
2024	89
Thereafter	480
Total lease payments	1,432
Less: Interest	(187)
Total lease liabilities	1,245
Remainder of 2020
Remainder of 2020	7
2021	35
2022	34
2023	32
2024	30
Thereafter	261
Total lease payments	399
Less: Interest	(74)
Total lease liabilities	325
Operating and Finance Lease Liabilities, Payments, Due [Abstract]
Remainder of 2020	124
2021	489
2022	216
2023	142
2024	119
Thereafter	741
Total lease payments	1,831
Less: Interest	(261)
Total lease liabilities	$ 1,570
Weighted average lease term, operating lease	6 years
Weighted average discount rate, operating lease	4.53%
Weighted average lease term, finance lease	11 years 9 months 18 days
Weighted average discount rate, finance lease	3.37%

Finance Lease, Liability, to be Paid, after Year Four

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Lessee, Operating Lease, Liability, to be Paid, after Year Four

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Operating and Finance Lease Liabilities, Payments, Due [Abstract]

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Operating and Finance Lease, Liability, Undiscounted Excess Amount

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Present value of lessee's discounted obligation for lease payments from finance lease.

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Amount of lessee's undiscounted obligation for lease payments for finance lease.

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Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for finance lease to be paid in remainder of current fiscal year.

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for finance lease.

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Weighted average discount rate for finance lease calculated at point in time.

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Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of lessee's undiscounted obligation for lease payment for operating lease.

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease having initial or remaining lease term in excess of one year to be paid in remainder of current fiscal year.

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

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Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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