Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Purchase Obligations

Future minimum payments required under these commitments are as follows:

		Purchase
		Obligations
(Dollars in millions)
2018	$	1,258
2019		671
2020		79
2021		45
2022		22
Thereafter		35
Total	$	2,110

Lease commitments

As of December 31, 2017, future minimum rental payments required under operating leases and rental receipts expected under operating leases that have noncancellable lease terms in excess of one year were as follows:

	OperatingLeases		OperatingLeases
	Future Minimum		Future Minimum
	RentalPayments		RentalReceipts
(Dollars in millions)
2018	$	160	$	80
2019		149		62
2020		136		35
2021		121		22
2022		106		9
Thereafter		766		6
Total	$	1,438	$	216