CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income	$ 490	$ 106
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	101	85
Provision for credit losses	2	7
Deferred income tax (benefit) provision	(17)	14
Stock-based compensation expense	18	14
Other, net	(2)	(2)
Changes in operating assets and liabilities:
Accounts receivable	138	85
Accounts payable and accrued expenses	(164)	(47)
Income taxes payable	163	(3)
Other assets and liabilities, net	2	(12)
Net cash provided by operating activities	731	247
Cash flows from investing activities:
Business acquisitions, net of cash acquired	0	(108)
Capital expenditures	(86)	(83)
Increase in investments and other assets	(7)	(15)
Net cash used in investing activities	(93)	(206)
Cash flows from financing activities:
Repayments of debt	(1)	(801)
Purchases of treasury stock	(410)	(75)
Exercise of stock options	17	80
Employee payroll tax withholdings on stock issued under stock-based compensation plans	(21)	(13)
Dividends paid	(75)	(71)
Distributions to noncontrolling interest partners	(29)	(7)
Other financing activities, net	(47)	(4)
Net cash used in financing activities	(566)	(891)
Net change in cash and cash equivalents and restricted cash	72	(850)
Cash and cash equivalents and restricted cash, beginning of period	1,158	1,192
Cash and cash equivalents and restricted cash, end of period	$ 1,230	$ 342