Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues:
Premiums										$ 37,009	$ 35,106	$ 32,712
Services										1,726	1,360	555
Investment income										391	366	329
Total revenues	9,557	9,651	9,699	[1]	10,219	9,056	9,301	9,284	9,191	39,126	36,832	33,596
Operating expenses:
Benefits										30,985	28,823	27,117
Operating costs										5,830	5,395	4,380
Depreciation and amortization										295	270	245
Total operating expenses										37,110	34,488	31,742
Income from operations										2,016	2,344	1,854
Interest expense										105	109	105
Income before income taxes	282	675	564	[1]	390	313	699	726	497	1,911	2,235	1,749
Provision for income taxes										689	816	650
Net income	$ 192	$ 426	$ 356	[1]	$ 248	$ 199	$ 445	$ 460	$ 315	$ 1,222	$ 1,419	$ 1,099
Basic earnings per common share	$ 1.21	$ 2.65	$ 2.19	[1]	$ 1.51	$ 1.22	$ 2.71	$ 2.76	$ 1.88	$ 7.56	$ 8.58	$ 6.55
Diluted earnings per common share	$ 1.19	$ 2.62	$ 2.16	[1]	$ 1.49	$ 1.20	$ 2.67	$ 2.71	$ 1.86	$ 7.47	$ 8.46	$ 6.47
Dividends declared per common share										$ 1.03	$ 0.75	$ 0.00

[1] Includes an expense of $46 million ($29 million after tax, or $0.18 per diluted common share) for a litigation settlement associated with our military services business.