Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Statement of Cash Flows [Abstract]
Proceeds from term deposits and sales of available-for-sale investments	$ 0	$ 1,084
Operating activities
Net income	740	612
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	289	182
Stock-based compensation	60	47
Deferred taxes	49	(38)
Amortization of Debt Discount (Premium)	0	(23)
Other	4	(17)
Changes in assets and liabilities:
Customer accounts receivable	(157)	(91)
Prepaid expenses and other current assets	(21)	(25)
Income taxes payable	79	31
Deferred revenue	257	237
Other current and non-current liabilities	(197)	(145)
Total adjustments	363	158
Net cash provided by operating activities	1,103	770
Investing activities
Capital expenditures	(96)	(92)
Capitalized software development costs	(61)	(44)
Cash paid for equity method investment	(70)	(60)
Increase in restricted cash and investments	(75)	11
Net cash provide by (used in) investing activities	(302)	899
Financing activities
Proceeds from (repayments of) commercial paper, net	(781)	(918)
Dividends to shareholders	(205)	(158)
Payments relating to treasury shares received for restricted stock tax payments and stock option exercises	(48)	(39)
Repurchases of common stock	0	(399)
Distributions of profits to non-controlling interest	(10)	(17)
Proceeds from (Payments for) Other Financing Activities	13	24
Net cash used in financing activities	(1,031)	(1,635)
Effect of exchange rate changes on cash and cash equivalents	(7)	(8)
Net increase (decrease) in cash and cash equivalents	(237)	26
Cash and cash equivalents, beginning of period	627	652
Cash and cash equivalents, end of period	390
Supplemental cash flow disclosure
Cash paid for income taxes	275	233
Cash paid for interest	$ 88	$ 91