Condensed Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities
Net income	$ 1,261	$ 1,030
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized capital gains	(14)	(20)
Stock-based compensation	73	68
Depreciation and amortization	312	238
Provision (benefit) for deferred income taxes	31	(6)
Changes in operating assets and liabilities, net of effect of businesses acquired:
Receivables	(89)	436
Other assets	(165)	(236)
Benefits payable	287	131
Other liabilities	24	121
Unearned revenues	(32)	(95)
Other, net	44	51
Net cash provided by operating activities	1,732	1,718
Cash flows from investing activities
Acquisitions, net of cash acquired	(161)	(288)
Proceeds from sale of business	33	0
Purchases of property and equipment	(310)	(304)
Purchases of investment securities	(2,665)	(2,166)
Maturities of investment securities	853	1,111
Proceeds from sales of investment securities	1,107	894
Net cash used in investing activities	(1,143)	(753)
Cash flows from financing activities
Receipts (withdrawals) from contract deposits, net	(201)	(347)
Repayment of long-term debt	0	(36)
Change in book overdraft	(51)	(29)
Common stock repurchases	(325)	(513)
Dividends paid	(125)	(124)
Excess tax benefit from stock-based compensation	6	21
Proceeds from stock option exercises and other	56	49
Net cash used in financing activities	(640)	(979)
Decrease in cash and cash equivalents	(51)	(14)
Cash and cash equivalents at beginning of period	1,306	1,377
Cash and cash equivalents at end of period	1,255	1,363
Supplemental cash flow disclosures:
Interest payments	82	65
Income tax payments, net	$ 724	$ 514