Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Premiums	$ 21,451	$ 20,797	$ 63,602	$ 62,561
Administrative fees and other revenue	1,529	1,300	4,435	4,053
Total operating revenue	22,980	22,097	68,037	66,614
Net investment income	250	220	708	628
Net realized gains on financial instruments	27	115	5	138
Other-than-temporary impairment losses on investments:
Total other-than-temporary impairment losses on investments	(8)	(6)	(20)	(23)
Portion of other-than-temporary impairment losses recognized in other comprehensive income	2	0	2	2
Other-than-temporary impairment losses recognized in income	(6)	(6)	(18)	(21)
Total revenues	23,251	22,426	68,732	67,359
Expenses
Benefit expense	18,185	18,104	52,959	53,564
Selling, general and administrative expense:
Selling expense	330	348	972	1,042
General and administrative expense	3,216	2,663	9,430	8,214
Total selling, general and administrative expense	3,546	3,011	10,402	9,256
Interest expense	188	150	564	575
Amortization of other intangible assets	91	42	265	124
(Gain) loss on extinguishment of debt	(1)	0	17	0
Total expenses	22,009	21,307	64,207	63,519
Income before income tax expense	1,242	1,119	4,525	3,840
Income tax expense	282	372	1,200	1,228
Net income	$ 960	$ 747	$ 3,325	$ 2,612
Net income per share
Basic net income per share	$ 3.70	$ 2.87	$ 12.89	$ 9.92
Diluted net income per share	3.62	2.80	12.58	9.70
Dividends per share	$ 0.75	$ 0.70	$ 2.25	$ 2.00