Condensed Consolidated Statements of Cash Flows (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities
Net income	$ 775,463	$ 598,844
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized capital gains	(5,109)	(7,976)
Stock-based compensation	40,978	39,627
Depreciation and amortization	150,583	132,046
Provision (benefit) for deferred income taxes	21,418	(81,267)
Changes in operating assets and liabilities, net of effect of businesses acquired:
Receivables	(587,374)	(501,482)
Other assets	(174,800)	73,683
Benefits payable	483,879	607,149
Other liabilities	202,069	219,163
Unearned revenues	19,449	(19,471)
Other, net	30,109	19,646
Net cash provided by operating activities	956,665	1,079,962
Cash flows from investing activities
Acquisitions, net of cash acquired	(10,952)	(1,669)
Purchases of property and equipment	(129,181)	(91,427)
Purchases of investment securities	(1,902,083)	(2,759,168)
Maturities of investment securities	731,204	1,014,032
Proceeds from sales of investment securities	432,006	1,091,282
Change in securities lending collateral	20,157	74,809
Net cash used in investing activities	(858,849)	(672,141)
Cash flows from financing activities
Receipts from CMS contract deposits	1,254,847	880,252
Withdrawals from CMS contract deposits	(1,066,478)	(643,976)
Change in securities lending payable	(20,157)	(74,809)
Change in book overdraft	(192,098)	(134,548)
Common stock repurchases	(300,788)	(57,869)
Excess tax benefit from stock-based compensation	11,287	1,264
Proceeds from stock option exercises and other	110,258	7,259
Net cash used in financing activities	(203,129)	(22,427)
(Decrease) increase in cash and cash equivalents	(105,313)	385,394
Cash and cash equivalents at beginning of period	1,673,137	1,613,588
Cash and cash equivalents at end of period	1,567,824	1,998,982
Supplemental cash flow disclosures:
Interest payments	56,958	55,855
Income tax payments, net	$ 407,416	$ 356,390