CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income	$ 99	$ 113
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	135	93
Deferred income taxes	20	(12)
Share-based compensation	24	16
Amortization of convertible senior notes and lease financing obligations	23	22
Other, net	14	13
Changes in operating assets and liabilities:
Receivables	(427)	(23)
Prepaid expenses and other assets	(116)	(63)
Medical claims and benefits payable	168	359
Amounts due government agencies	503	453
Accounts payable and accrued liabilities	1	34
Deferred revenue	157	(129)
Income taxes	32	30
Net cash provided by operating activities	633	906
Investing activities:
Purchases of investments	(1,444)	(1,311)
Proceeds from sales and maturities of investments	1,512	863
Purchases of property, equipment and capitalized software	(143)	(101)
Change in restricted investments	4	(5)
Net cash paid in business combinations	(48)	(77)
Other, net	(12)	(34)
Net cash used in investing activities	(131)	(665)
Financing activities:
Proceeds from common stock offering, net of issuance costs	0	373
Proceeds from employee stock plans	10	8
Other, net	1	3
Net cash provided by financing activities	11	384
Net increase in cash and cash equivalents	513	625
Cash and cash equivalents at beginning of period	2,329	1,539
Cash and cash equivalents at end of period	2,842	2,164
Schedule of non-cash investing and financing activities:
Common stock used for share-based compensation	(8)	(9)
Details of change in fair value of derivatives, net:
Change in fair value of derivatives, net	0	0
Details of business combinations:
Fair value of assets acquired	(186)	(69)
Fair value of liabilities assumed	28	0
Purchase price amounts accrued/received (paid)	8	(8)
Reversal of amounts advanced to sellers in prior year	102	0
Net cash paid in business combinations	(48)	(77)
(Loss) gain on 1.125% Call Option
Details of change in fair value of derivatives, net:
Change in fair value of derivatives, net	(60)	161
Gain (loss) on 1.125% Conversion Option
Details of change in fair value of derivatives, net:
Change in fair value of derivatives, net	$ 60	$ (161)