Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net income	$ 492	$ 474
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	158	138
Stock-based compensation	29	29
Deferred taxes	(28)	(6)
Other	(21)	1
Changes in assets and liabilities:
Customer accounts receivable	(227)	(259)
Other current and non-current assets	15	(32)
Section 31 fees payable	(35)	(8)
Deferred revenue	347	343
Other current and non-current liabilities	(76)	(107)
Total adjustments	162	99
Net cash provided by operating activities	654	573
Investing activities:
Capital expenditures	(26)	(14)
Capitalized software development costs	(39)	(37)
Cash paid for acquisitions	(19)	(400)
Return of capital from equity method investment	44	0
Purchases of investments	0	(304)
Net cash used in investing activities	(40)	(755)
Financing activities:
Proceeds from commercial paper, net of repayments	54	789
Repurchases of common stock	(440)	(300)
Dividends to stockholders	(157)	(140)
Payments relating to treasury shares received for restricted stock tax payments and stock option exercises	(57)	(72)
Other	4	(7)
Net cash provided by (used in) financing activities	(596)	270
Effect of exchange rate changes on cash, cash equivalents and restricted cash and cash equivalents	1	2
Net increase in cash, cash equivalents, and restricted cash and cash equivalents	19	90
Cash, cash equivalents, and restricted cash and cash equivalents, beginning of period	1,872	1,568
Cash, cash equivalents, and restricted cash and cash equivalents, end of period	1,891	1,658
Supplemental cash flow disclosure:
Cash paid for income taxes	78	144
Cash paid for interest	$ 79	$ 27