Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of Rental Expense for Property and Equipment Under Operating Lease Agreements

Rental expense for property and equipment under all operating lease agreements is as follows:

(in millions)	Year ended December 31,
	2017			2016			2015
Gross rental expense	$	177		$	179		$	182
Less: sublease revenue	(17		)	(16		)	(14		)
Less: rent credit	—			—			(4		)
Net rental expense	$	160		$	163		$	164

Schedule of Future Minimum Rental Commitments

Cash amounts for future minimum rental commitments under existing non-cancelable leases with a remaining term of more than one year, along with minimum sublease rental income to be received under non-cancelable subleases are shown in the following table.

(in millions)	Rent commitment		Sublease income			Net rent
2018	$	122	$	(17	)	$	105
2019	109		(17		)	92
2020	83		(3		)	80
2021	71		—			71
2022	69		—			69
2023 and beyond	516		—			516
Total	$	970	$	(37	)	$	933