Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash provided by operating activities
Net income	$ 143	$ 127
Non-cash charges to net income:
Depreciation and amortization	54	51
Mechanical stores expense	15	15
Deferred income taxes	8	(4)
Charge for fair value markup of acquired inventory		5
Other	8	12
Changes in working capital:
Accounts receivable and prepaid expenses	(56)	12
Inventories	(21)	(40)
Accounts payable and accrued liabilities	(57)	(48)
Margin accounts	16	6
Other	40	(5)
Cash provided by operating activities	150	131
Cash used for investing activities
Capital expenditures and mechanical stores purchases, net proceeds on disposals	(95)	(72)
Payments for acquisitions		(13)
Short-term investments	3	(8)
Other	6
Cash used for investing activities	(86)	(93)
Cash used for financing activities
Proceeds from borrowings	46	108
Payments on debt	(258)	(55)
Repurchases of common stock		(123)
Issuances of common stock for share-based compensation, net of settlements	(3)	(7)
Dividends paid, including to non-controlling interests	(46)	(44)
Cash used for financing activities	(261)	(121)
Effects of foreign exchange rate changes on cash	3	6
Decrease in cash and cash equivalents	(194)	(77)
Cash and cash equivalents, beginning of period	595	512
Cash and cash equivalents, end of period	$ 401	$ 435