Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 367	$ 441
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	136	133
Deferred income taxes	(19)	(42)
Stock-based compensation expense	55	66
Other	144	(7)
Changes in assets and liabilities:
Trade accounts receivable	13	(131)
Other current and noncurrent assets	26	90
Accounts payable	44	49
Deferred revenues, current and noncurrent	59	56
Other current and noncurrent liabilities	(328)	(386)
Net cash provided by operating activities	497	269
Cash flows from investing activities:
Purchases of property and equipment	(112)	(106)
Purchases of available-for-sale investment securities	0	(243)
Proceeds from maturity or sale of available-for-sale investment securities	0	650
Purchases of held-to-maturity investment securities	(202)	(94)
Proceeds from maturity of held-to-maturity investment securities	154	348
Purchases of other investments	(54)	(31)
Proceeds from maturity or sale of other investments	28	29
Payments for business combinations, net of cash acquired	(86)	(197)
Net cash (used in) provided by investing activities	(272)	356
Cash flows from financing activities:
Issuance of common stock under stock-based compensation plans	40	50
Repurchases of common stock	(511)	(771)
Repayment of term loan borrowings and finance lease obligations	(13)	(2)
Borrowings under the revolving credit facility	1,740	0
Dividends paid	(121)	(116)
Net cash provided by (used in) financing activities	1,135	(839)
Effect of exchange rate changes on cash and cash equivalents	(119)	3
Increase (decrease) in cash and cash equivalents	1,241	(211)
Cash and cash equivalents, beginning of year	2,645	1,161
Cash and cash equivalents, end of period	$ 3,886	$ 950