Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues
Premiums	$ 19,786.1	$ 18,513.0	$ 58,723.0	$ 54,639.8
Administrative fees	1,330.0	1,249.6	3,956.8	3,706.2
Other revenue	9.1	8.8	29.3	35.1
Total operating revenue	21,125.2	19,771.4	62,709.1	58,381.1
Net investment income	200.9	161.2	566.9	515.5
Net realized gains (losses) on financial instruments	88.8	(11.9)	(23.8)	126.9
Other-than-temporary impairment losses on investments:
Total other-than-temporary impairment losses on investments	(15.1)	(26.6)	(134.1)	(68.2)
Portion of other-than-temporary impairment losses recognized in other comprehensive income	4.1	7.5	30.5	13.3
Other-than-temporary impairment losses recognized in income	(11.0)	(19.1)	(103.6)	(54.9)
Total revenues	21,403.9	19,901.6	63,148.6	58,968.6
Expenses
Benefit expense	16,922.5	15,469.1	49,266.5	44,801.4
Selling, general and administrative expense:
Selling expense	338.5	359.1	1,039.9	1,091.1
General and administrative expense	2,786.1	2,721.3	8,254.0	8,175.3
Total selling, general and administrative expense	3,124.6	3,080.4	9,293.9	9,266.4
Interest expense	172.9	164.8	545.7	473.3
Amortization of other intangible assets	47.4	60.0	145.7	172.6
Gain on extinguishment of debt	0.0	(2.3)	0.0	(1.8)
Total expenses	20,267.4	18,772.0	59,251.8	54,711.9
Income before income tax expense	1,136.5	1,129.6	3,896.8	4,256.7
Income tax expense	518.7	474.8	1,795.4	1,877.6
Net income	$ 617.8	$ 654.8	$ 2,101.4	$ 2,379.1
Net income per share
Basic net income per share	$ 2.35	$ 2.51	$ 8.00	$ 9.03
Diluted net income per share	2.30	2.43	7.84	8.66
Dividends per share	$ 0.650	$ 0.625	$ 1.950	$ 1.875