Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 1,971.2	$ 1,582.1
Investments available-for-sale, at fair value:
Fixed maturity securities (amortized cost of $17,600.8 and $16,826.7)	18,004.0	17,038.2
Equity securities (cost of $1,374.0 and $1,168.5)	1,963.5	1,735.5
Other invested assets, current	25.9	16.3
Accrued investment income	173.6	168.8
Premium and self-funded receivables	4,457.5	3,968.7
Other receivables	1,234.0	1,063.3
Income taxes receivable	0	235.7
Securities lending collateral	1,325.0	969.8
Deferred tax assets, net	234.5	383.0
Other current assets	2,417.6	1,677.5
Assets held for sale	0	906.9
Total current assets	31,806.8	29,745.8
Long-term investments available-for-sale, at fair value:
Fixed maturity securities (amortized cost of $504.6 and $455.9)	502.4	449.9
Equity securities (cost of $26.8 and $27.4)	31.0	31.3
Other invested assets, long-term	1,593.8	1,542.6
Property and equipment, net	1,811.7	1,801.5
Goodwill	16,916.7	16,917.2
Other intangible assets	8,387.3	8,441.0
Other noncurrent assets	635.8	645.2
Total assets	61,685.5	59,574.5
Liabilities and shareholders' equity
Medical claims payable	6,707.1	6,127.2
Reserves for future policy benefits	65.7	63.1
Other policyholder liabilities	2,020.4	2,073.2
Total policy liabilities	8,793.2	8,263.5
Unearned income	1,073.0	822.7
Accounts payable and accrued expenses	4,113.1	3,426.3
Accrued Income Taxes, Current	97.7	0
Security trades pending payable	177.5	95.2
Securities lending payable	1,324.6	969.7
Short-term borrowings	590.0	400.0
Current portion of long-term debt	518.7	518.0
Other current liabilities	1,805.9	1,674.7
Liabilities held for sale	0	181.4
Total current liabilities	18,493.7	16,351.5
Long-term debt, less current portion	13,932.1	13,573.6
Reserves for future policy benefits, noncurrent	738.9	723.0
Deferred tax liabilities, net	3,343.1	3,325.2
Other noncurrent liabilities	832.4	836.0
Total liabilities	37,340.2	34,809.3
Commitment and contingencies-Note 9
Shareholders' equity
Preferred stock, without par value, shares authorized – 100,000,000; shares issued and outstanding – none	0	0
Common stock, par value $0.01, shares authorized – 900,000,000; shares issued and outstanding – 281,912,262 and 293,273,830	2.9	2.9
Additional paid-in capital	10,003.5	10,765.2
Retained earnings	14,011.5	13,813.9
Accumulated other comprehensive income	327.4	183.2
Total shareholders' equity	24,345.3	24,765.2
Total liabilities and shareholders' equity	$ 61,685.5	$ 59,574.5