CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 557	$ 529
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	197	186
Provision for doubtful accounts	241	242
Deferred income tax provision	90	19
Stock-based compensation expense	54	52
Gain on disposition of business	0	(118)
Other, net	(5)	(15)
Changes in operating assets and liabilities:
Accounts receivable	(265)	(316)
Accounts payable and accrued expenses	(3)	43
Income taxes payable	0	74
Termination of interest rate swap agreements	0	54
Other assets and liabilities, net	(14)	15
Net cash provided by operating activities	852	765
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(299)	(139)
Proceeds from disposition of businesses	1	270
Escrow proceeds associated with disposition of business	25	0
Capital expenditures	(170)	(165)
Decrease (increase) in investments and other assets	4	(11)
Net cash used in investing activities	(439)	(45)
Cash flows from financing activities:
Proceeds from borrowings	0	1,869
Repayments of debt	(5)	(1,722)
Purchases of treasury stock	(350)	(440)
Exercise of stock options	125	63
Employee payroll tax withholdings on stock issued under stock-based compensation plans	(23)	(10)
Dividends paid	(186)	(168)
Distributions to noncontrolling interests	(38)	(31)
Other financing activities, net	55	(8)
Net cash used in financing activities	(422)	(447)
Net change in cash and cash equivalents	(9)	273
Cash and cash equivalents, beginning of period	359	133
Cash and cash equivalents, end of period	$ 350	$ 406