CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 1,667	$ 890
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	302	263
Provision for credit losses	3	18
Deferred income tax (benefit) provision	(87)	12
Stock-based compensation expense	60	63
Gain on disposition of joint venture	(314)	0
Other, net	(48)	(60)
Changes in operating assets and liabilities:
Accounts receivable	45	(355)
Accounts payable and accrued expenses	36	514
Income taxes payable	49	95
Termination of interest rate swap agreements	0	40
Other assets and liabilities, net	39	(16)
Net cash provided by operating activities	1,752	1,464
Cash flows from investing activities:
Business acquisitions, net of cash acquired	(251)	(329)
Capital expenditures	(259)	(256)
Proceeds from disposition of joint venture	755	0
Decrease (increase) in investments and other assets	3	(19)
Net cash provided by (used in) investing activities	248	(604)
Cash flows from financing activities:
Proceeds from borrowings	0	749
Repayments of debt	(2)	(1,002)
Purchases of treasury stock	(1,910)	(75)
Exercise of stock options	108	144
Employee payroll tax withholdings on stock issued under stock-based compensation plans	(22)	(13)
Dividends paid	(232)	(222)
Distributions to noncontrolling interest partners	(75)	(34)
Other financing activities, net	(38)	6
Net cash used in financing activities	(2,171)	(447)
Net change in cash and cash equivalents and restricted cash	(171)	413
Cash and cash equivalents and restricted cash, beginning of period	1,158	1,192
Cash and cash equivalents and restricted cash, end of period	$ 987	$ 1,605