Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 3,608.9	$ 4,075.3
Investments available-for-sale, at fair value:
Fixed maturity securities (amortized cost of $17,054.5 and $16,991.8)	17,377.3	17,163.1
Equity securities (cost of $3,098.1 and $1,076.1)	3,599.2	1,468.5
Other invested assets, current	17.2	15.8
Accrued investment income	162.5	164.5
Premium and self-funded receivables	6,184.9	5,860.8
Other receivables	2,266.5	2,536.6
Income taxes receivable	341.9	168.7
Securities lending collateral	455.1	1,079.8
Other current assets	2,249.3	1,781.8
Total current assets	36,262.8	34,314.9
Long-term investments available-for-sale, at fair value:
Fixed maturity securities (amortized cost of $556.0 and $524.6)	560.8	524.4
Equity securities (cost of $26.7 and $27.2)	32.8	31.4
Other invested assets, long-term	3,343.8	2,240.5
Property and equipment, net	2,174.9	1,977.9
Goodwill	19,231.2	17,561.2
Other intangible assets	8,368.4	7,964.9
Other noncurrent assets	565.3	467.9
Total assets	70,540.0	65,083.1
Liabilities and shareholders' equity
Medical claims payable	7,991.5	7,892.6
Reserves for future policy benefits	69.9	71.8
Other policyholder liabilities	2,950.3	2,221.1
Total policy liabilities	11,011.7	10,185.5
Unearned income	860.3	971.9
Accounts payable and accrued expenses	5,024.4	4,014.9
Security trades pending payable	112.6	93.5
Securities lending payable	454.4	1,078.9
Short-term borrowings	1,275.0	440.0
Current portion of long-term debt	1,274.6	928.4
Other current liabilities	3,343.0	3,581.3
Total current liabilities	23,356.0	21,294.4
Long-term debt, less current portion	17,382.2	14,358.5
Reserves for future policy benefits, noncurrent	647.3	666.1
Deferred tax liabilities, net	1,726.5	2,779.9
Other noncurrent liabilities	925.1	883.8
Total liabilities	44,037.1	39,982.7
Commitments and contingencies-Note 13
Shareholders' equity
Preferred stock, without par value, shares authorized - 100,000,000; shares issued and outstanding - none	0.0	0.0
Common stock, par value $0.01, shares authorized - 900,000,000; shares issued and outstanding - 256,084,913 and 263,747,395	2.6	2.6
Additional paid-in capital	8,547.4	8,805.1
Retained earnings	18,054.4	16,560.6
Accumulated other comprehensive loss	(101.5)	(267.9)
Total shareholders' equity	26,502.9	25,100.4
Total liabilities and shareholders' equity	$ 70,540.0	$ 65,083.1