Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 975	$ 914	$ 1,187
Adjustments to reconcile net income to net cash provided by operating activities from continuing operations:
Depreciation and other amortization	1,077	615	382
Amortization of acquisition-related intangible assets	2,133	1,036	163
Amortization of financing costs, debt discounts and other	47	127	11
Net foreign currency gain on financing activities	0	(50)	0
Share-based compensation	369	229	73
Deferred income taxes	71	47	133
Gain on sale of businesses	(464)	(15)	(227)
Income from investments in unconsolidated affiliates	0	(29)	(10)
Distributions from unconsolidated affiliates	42	23	2
Settlement of interest rate hedge contracts	0	(183)	0
Non-cash impairment charges	124	48	3
Other operating activities	(16)	(3)	4
Changes in assets and liabilities, net of effects from acquisitions and dispositions:
Trade accounts receivable	320	(7)	(108)
Prepaid expenses and other assets	(167)	(82)	(6)
Contract costs	(289)	(212)	(137)
Accounts payable and other liabilities	(146)	238	116
Contract liabilities	71	99	(34)
Net cash provided by operating activities from continuing operations	4,147	2,795	1,552
Cash flows from investing activities:
Capital expenditures, including capitalized software and other intangibles	(900)	(721)	(360)
Proceeds from sale of businesses	579	51	419
Payments for acquisitions of businesses, net of cash acquired and including working capital adjustments	(139)	(16,005)	(712)
Distributions from unconsolidated affiliates	109	113	0
Purchases of investments	(1)	(45)	(3)
Other investing activities	11	5	(7)
Net cash used in investing activities from continuing operations	(341)	(16,602)	(663)
Cash flows from financing activities:
Debt proceeds	8,897	20,030	5,039
Debt repayments	(10,918)	(5,043)	(4,005)
Short-term borrowings, net	(6)	0	0
Payments of debt financing, redemption and other costs	(16)	(247)	0
Proceeds from issuance of treasury stock	133	156	75
Purchases of treasury stock, including employee shares withheld for tax obligations	(1,826)	(561)	(1,946)
Distributions paid to noncontrolling interests and redeemable noncontrolling interests	(104)	(118)	0
Other financing activities	4	(26)	(5)
Net cash (used in) provided by financing activities from continuing operations	(3,836)	14,191	(842)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	16	1	0
Net change in cash, cash equivalents and restricted cash from continuing operations	(14)	385	47
Net cash flows from discontinued operations	0	133	43
Cash, cash equivalents and restricted cash, beginning balance	933	415	325
Cash, cash equivalents and restricted cash, ending balance	919	933	415
Discontinued operations cash flow information:
Net cash used in operating activities	0	0	(7)
Net cash provided by investing activities	0	133	50
Net cash flows from discontinued operations	$ 0	$ 133	$ 43