Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities
Net income	$ 1,220,223	$ 992,065
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized capital gains	(7,255)	(12,286)
Stock-based compensation	52,778	52,104
Depreciation and amortization	225,164	196,603
Provision (benefit) for deferred income taxes	12,102	(115,923)
Changes in operating assets and liabilities, net of effect of businesses acquired:
Receivables	(77,299)	15,592
Other assets	(205,092)	119,728
Benefits payable	399,122	504,337
Other liabilities	391,892	520,771
Unearned revenues	1,819,931	(15,073)
Other, net	44,414	31,253
Net cash provided by operating activities	3,875,980	2,289,171
Cash flows from investing activities
Acquisitions, net of cash acquired	(13,652)	(10,120)
Purchases of property and equipment	(215,926)	(152,432)
Purchases of investment securities	(2,667,353)	(3,582,352)
Maturities of investment securities	1,084,062	1,492,601
Proceeds from sales of investment securities	625,461	1,298,912
Change in securities lending collateral	44,211	88,321
Net cash used in investing activities	(1,143,197)	(865,070)
Cash flows from financing activities
Receipts from CMS contract deposits	2,135,321	1,319,874
Withdrawals from CMS contract deposits	(1,909,875)	(1,117,655)
Change in securities lending payable	(44,211)	(88,321)
Change in book overdraft	(110,798)	(133,235)
Common stock repurchases	(540,234)	(108,170)
Dividends paid	(41,494)	0
Excess tax benefit from stock-based compensation	12,246	1,406
Proceeds from stock option exercises and other	112,530	11,264
Net cash used in financing activities	(386,515)	(114,837)
Increase in cash and cash equivalents	2,346,268	1,309,264
Cash and cash equivalents at beginning of period	1,673,137	1,613,588
Cash and cash equivalents at end of period	4,019,405	2,922,852
Supplemental cash flow disclosures:
Interest payments	67,894	66,403
Income tax payments, net	$ 717,654	$ 632,745