Leases Leases - Schedule of Future Minimum Rental Payments for Operating Leases (Details) $ in Millions	Dec. 31, 2018 USD ($)
Minimum Lease Payments
2020	$ 136
2021	125
2022	115
2023	103
2024	91
Thereafter	182
Net minimum lease commitments	752
Minimum Sublease Income
2020	(58)
2021	(2)
2022	(1)
2023	0
2024	0
Thereafter	(1)
Net minimum lease commitments	(62)
Net
2020	78
2021	123
2022	114
2023	103
2024	91
Thereafter	181
Net minimum lease commitments	$ 690

Operating Leases, Net Future Minimum Payments, Due

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Operating Leases, Net Future Minimum Payments Due, Fiscal Year Maturity [Abstract]

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Operating Leases, Net Future Minimum Payments, Due in Five Years

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Operating Leases, Net Future Minimum Payments, Due in Four Years

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Operating Leases, Net Future Minimum Payments, Due in Three Years

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Operating Leases, Net Future Minimum Payments, Due in Two Years

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Operating Leases, Net Future Minimum Payments, Due Thereafter

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Operating Leases, Net Future Minimum Payments, Next Twelve Months

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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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Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

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Future rental payments receivable within one year of the balance sheet date under an operating lease.

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Future rental payments receivable within the fourth year from the balance sheet date under an operating lease.

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Future rental payments receivable within the third year from the balance sheet date under an operating lease.

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Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

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