Revenue (Details) - USD ($) $ in Millions		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales and operating revenues		$ 2,574	$ 2,292
Cost of sales (exclusive of depreciation and amortization shown below)		2,198	1,929
Inventory	$ 864	911		$ 869
Prepayments and other (including contract assets)	297	340		291
Retained earnings (accumulated deficit)	(947)	(902)		(946)
Increase/(decrease) in inventories		(34)	(45)
Increase/(decrease) in prepayments and other current assets		(45)	$ (57)
Calculated under Revenue Guidance in Effect before Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales and operating revenues		2,576
Cost of sales (exclusive of depreciation and amortization shown below)		2,200
Inventory		919		869
Prepayments and other (including contract assets)		331		291
Retained earnings (accumulated deficit)		(903)		$ (946)
Increase/(decrease) in inventories		(36)
Increase/(decrease) in prepayments and other current assets		(43)
Adjustments Due to ASU 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect on retained earnings	1	1
Adjustments Due to ASU 2014-09 | Difference between Revenue Guidance in Effect before and after Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net sales and operating revenues		2
Cost of sales (exclusive of depreciation and amortization shown below)		2
Inventory	(5)	(8)
Prepayments and other (including contract assets)	6	9
Retained earnings (accumulated deficit)	1	1
Increase/(decrease) in inventories		2
Increase/(decrease) in prepayments and other current assets		(2)
Adjustments Due to ASU 2016-16 (a)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect on retained earnings		$ 2
Inventory	0
Prepayments and other (including contract assets)	0
Retained earnings (accumulated deficit)	$ (2)