Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Premiums									$ 54,941	$ 52,380	$ 53,021
Services									1,457	982	969
Investment income									514	405	389
Total revenues	$ 14,168	$ 14,206	$ 14,259	$ 14,279	$ 13,189	$ 13,282	$ 13,534	$ 13,762	56,912	53,767	54,379
Operating expenses:
Benefits									45,882	43,496	45,007
Operating costs									7,525	6,567	7,173
Merger termination fee and related costs, net									0	(936)	104
Depreciation and amortization									405	378	354
Total operating expenses									53,812	49,505	52,638
Income from operations									3,100	4,262	1,741
Loss on sale of business									786	0	0
Interest expense									218	242	189
Other expense, net									33	0	0
Income (loss) before income taxes and equity in net earnings	436	901	19	707	490	799	1,042	1,689	2,063	4,020	1,552
Provision for income taxes									391	1,572	938
Equity in net earnings of Kindred at Home									11	0	0
Net income	$ 355	$ 644	$ 193	$ 491	$ 184	$ 499	$ 650	$ 1,115	$ 1,683	$ 2,448	$ 614
Basic earnings per common share (in USD per share)	$ 2.60	$ 4.68	$ 1.40	$ 3.56	$ 1.30	$ 3.46	$ 4.49	$ 7.54	$ 12.24	$ 16.94	$ 4.11
Diluted earnings per common share (in USD per share)	$ 2.58	$ 4.65	$ 1.39	$ 3.53	$ 1.29	$ 3.44	$ 4.46	$ 7.49	$ 12.16	$ 16.81	$ 4.07