Condensed 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	$ 9,698	$ 9,088	$ 29,267	$ 28,029
Services	528	467	1,581	1,251
Investment income	93	96	278	289
Total revenues	10,319	9,651	31,126	29,569
Operating expenses:
Benefits	8,075	7,467	24,361	23,469
Operating costs	1,540	1,408	4,447	4,175
Depreciation and amortization	83	75	243	218
Total operating expenses	9,698	8,950	29,051	27,862
Income from operations	621	701	2,075	1,707
Interest expense	35	26	105	78
Income before income taxes	586	675	1,970	1,629
Provision for income taxes	218	249	709	599
Net income	$ 368	$ 426	$ 1,261	$ 1,030
Basic earnings per common share	$ 2.34	$ 2.65	$ 7.98	$ 6.34
Diluted earnings per common share	$ 2.31	$ 2.62	$ 7.90	$ 6.27
Dividends declared per common share	$ 0.27	$ 0.26	$ 0.80	$ 0.77