Lease Commitments - Lease Maturity Prior to Topic 842 (Details) $ in Millions	Dec. 31, 2018 USD ($)
Gross rental commitments
2020	$ 303
2021	253
2022	221
2023	182
2024	148
Thereafter	472
Total minimum payments required	1,579
Rentals from subleases
2020	(34)
2021	(30)
2022	(30)
2023	(30)
2024	(12)
Thereafter	(5)
Total minimum payments required	(141)
Net rental commitments
2020	269
2021	223
2022	191
2023	152
2024	136
Thereafter	467
Total minimum payments required	$ 1,438

Operating Lease, Future Minimum Payments Due, Future Minimum Sublease Rental Payments, After Year Five

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Operating Lease Future Minimum Payments Due Future Minimum Sublease Rentals

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Operating Lease, Future Minimum Payments Due, Net Of Sublease Income, Next Twelve Months

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Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, Year Two

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Operating Leases, Future Minimum Payments Net Of Sublease Rentals, Due After Year Five

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Operating Leases, Future Minimum Payments Net Of Sublease Rentals, Due In Five Years

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Operating Leases, Future Minimum Payments Net Of Sublease Rentals, Due In Four Years

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Operating Leases, Future Minimum Payments Net Of Sublease Rentals, Due In Three Years

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Operating Leases, Future Minimum Payments Net Of Sublease Rentals, Due In Two Years

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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