CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 649	$ 557
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	228	197
Provision for doubtful accounts	2	5
Deferred income tax provision	52	90
Stock-based compensation expense	53	54
Other, net	7	(5)
Changes in operating assets and liabilities:
Accounts receivable	(166)	(29)
Accounts payable and accrued expenses	51	(3)
Income taxes payable	(1)	0
Other assets and liabilities, net	30	(14)
Net cash provided by operating activities	905	852
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(219)	(299)
Capital expenditures	(232)	(170)
(Increase) decrease in investments and other assets	(4)	5
Net cash used in investing activities	(455)	(464)
Cash flows from financing activities:
Proceeds from borrowings	1,630	0
Repayments of debt	(1,665)	(5)
Purchases of treasury stock	(150)	(350)
Exercise of stock options	95	125
Employee payroll tax withholdings on stock issued under stock-based compensation plans	(20)	(23)
Dividends paid	(198)	(186)
Distributions to noncontrolling interests	(41)	(38)
Sale of noncontrolling interest in subsidiaries	12	0
Other financing activities, net	13	55
Net cash used in financing activities	(324)	(422)
Net change in cash and cash equivalents and restricted cash	126	(34)
Cash and cash equivalents and restricted cash, beginning of period	137	384
Cash and cash equivalents and restricted cash, end of period	263	350
Cash and cash equivalents	137
Cash and cash equivalents and restricted cash, end of period	$ 137	$ 384