Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 728	$ 950
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	273	266
Deferred income taxes	(93)	(180)
Stock-based compensation expense	120	120
Other	187	(26)
Changes in assets and liabilities:
Trade accounts receivable	78	(129)
Other current and noncurrent assets	171	51
Accounts payable	103	2
Deferred revenues, current and noncurrent	19	(2)
Other current and noncurrent liabilities	(110)	(208)
Net cash provided by operating activities	1,476	844
Cash flows from investing activities:
Purchases of property and equipment	(205)	(202)
Purchases of available-for-sale investment securities	0	(333)
Proceeds from maturity or sale of available-for-sale investment securities	0	2,107
Purchases of held-to-maturity investment securities	(202)	(406)
Proceeds from maturity of held-to-maturity investment securities	346	691
Purchases of other investments	(264)	(310)
Proceeds from maturity or sale of other investments	283	308
Payments for business combinations, net of cash acquired	(489)	(232)
Net cash (used in) provided by investing activities	(531)	1,623
Cash flows from financing activities:
Issuance of common stock under stock-based compensation plans	76	90
Repurchases of common stock	(585)	(1,825)
Repayment of Term Loan borrowings and finance lease and earnout obligations	(25)	(9)
Borrowings under the revolving credit facility	1,740	0
Dividends paid	(242)	(232)
Net cash provided by (used in) financing activities	964	(1,976)
Effect of exchange rate changes on cash and cash equivalents	(132)	8
Increase in cash and cash equivalents	1,777	499
Cash and cash equivalents, beginning of year	2,645	1,161
Cash and cash equivalents, end of period	$ 4,422	$ 1,660