Consolidated Statements Of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues
Premiums	$ 16,580.9	$ 14,037.1	$ 49,509.5	$ 42,336.6
Administrative fees	1,027.8	955.6	3,006.4	2,928.9
Other revenue	124.3	141.0	360.6	191.7
Total operating revenue	17,733.0	15,133.7	52,876.5	45,457.2
Net investment income	167.6	168.6	482.8	507.0
Net realized gains on investments	95.4	54.6	166.4	232.0
Other-than-temporary impairment losses on investments:
Total other-than-temporary impairment losses on investments	(27.1)	(3.8)	(74.0)	(24.0)
Portion of other-than-temporary impairment losses recognized in other comprehensive income	0.9	0	0.9	3.4
Other-than-temporary impairment losses recognized in income	(26.2)	(3.8)	(73.1)	(20.6)
Total revenues	17,969.8	15,353.1	53,452.6	46,175.6
Expenses
Benefit expense	14,075.0	11,984.8	41,656.3	35,849.8
Selling, general and administrative expense:
Selling expense	377.3	390.2	1,139.9	1,176.5
General and administrative expense	2,202.7	1,688.4	6,275.6	5,149.6
Total selling, general and administrative expense	2,580.0	2,078.6	7,415.5	6,326.1
Cost of products	68.6	66.5	196.0	73.2
Interest expense	151.5	133.6	456.9	360.3
Amortization of other intangible assets	66.6	63.9	202.2	182.1
Loss on extinguishment of debt	145.3	0	145.3	0
Total expenses	17,087.0	14,327.4	50,072.2	42,791.5
Income before income tax expense	882.8	1,025.7	3,380.4	3,384.1
Income tax expense	226.6	334.5	1,038.9	1,192.8
Net income	$ 656.2	$ 691.2	$ 2,341.5	$ 2,191.3
Net income per share
Basic	$ 2.21	$ 2.17	$ 7.81	$ 6.70
Diluted	$ 2.16	$ 2.15	$ 7.69	$ 6.63
Dividends per share	$ 0.3750	$ 0.2875	$ 1.1250	$ 0.8625