Consolidated Statements of Changes in Equity - USD ($) shares in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Net Unrealized Gains (Losses) on Investments [Member]	Foreign Currency Translation Losses [Member]	Nonredeemable noncontrolling interests [Member]
Balance at Dec. 31, 2012	$ 31,178,000,000	$ 10,000,000	$ 66,000,000	$ 30,664,000,000	$ 516,000,000	$ (78,000,000)	$ 0
Balance (in shares) at Dec. 31, 2012		1,019
Net earnings attributable to UnitedHealth Group common stockholders	5,625,000,000			5,625,000,000
Net earnings attributable to nonredeemable noncontrolling interest							0
Net earnings including portion attributable to nonredeemable noncontrolling interest	5,625,000,000
Other comprehensive income (loss)	(1,346,000,000)				(462,000,000)	(884,000,000)
Issuances of common stock, and related tax effects (in shares)		17
Issuances of common stock, and related tax effects	431,000,000	$ 0	431,000,000
Share-based compensation, and related tax benefits	406,000,000		406,000,000
Common stock repurchases (in shares)		(48)
Common stock repurchases	(3,170,000,000)	$ 0	(984,000,000)	(2,186,000,000)
Acquisitions of redeemable noncontrolling interests and related tax effects	81,000,000		81,000,000
Cash dividends paid on common stock	(1,056,000,000)			(1,056,000,000)
Balance at Dec. 31, 2013	32,149,000,000	$ 10,000,000	0	33,047,000,000	54,000,000	(962,000,000)	0
Balance (in shares) at Dec. 31, 2013		988
Net earnings attributable to UnitedHealth Group common stockholders	5,619,000,000			5,619,000,000
Net earnings attributable to nonredeemable noncontrolling interest							0
Net earnings including portion attributable to nonredeemable noncontrolling interest	5,619,000,000
Other comprehensive income (loss)	(484,000,000)				169,000,000	(653,000,000)
Issuances of common stock, and related tax effects (in shares)		15
Issuances of common stock, and related tax effects	146,000,000	$ 0	146,000,000
Share-based compensation, and related tax benefits	394,000,000		394,000,000
Common stock repurchases (in shares)		(49)
Common stock repurchases	(4,008,000,000)	$ 0	(540,000,000)	(3,468,000,000)
Cash dividends paid on common stock	(1,362,000,000)			(1,362,000,000)
Balance at Dec. 31, 2014	$ 32,454,000,000	$ 10,000,000	0	33,836,000,000	223,000,000	(1,615,000,000)	0
Balance (in shares) at Dec. 31, 2014	954	954
Net earnings attributable to UnitedHealth Group common stockholders	$ 5,813,000,000			5,813,000,000
Net earnings attributable to nonredeemable noncontrolling interest							26,000,000
Net earnings including portion attributable to nonredeemable noncontrolling interest	5,839,000,000
Other comprehensive income (loss)	(1,942,000,000)				(167,000,000)	(1,775,000,000)
Issuances of common stock, and related tax effects (in shares)		10
Issuances of common stock, and related tax effects	127,000,000	$ 0	127,000,000
Share-based compensation, and related tax benefits	589,000,000		589,000,000
Common stock repurchases (in shares)		(11)
Common stock repurchases	(1,200,000,000)	$ 0	(462,000,000)	(738,000,000)
Cash dividends paid on common stock	(1,786,000,000)			(1,786,000,000)
Redeemable noncontrolling interests fair value and other adjustments	(225,000,000)		(225,000,000)
Acquisition of nonredeemable noncontrolling interest	9,000,000						9,000,000
Distributions to nonredeemable noncontrolling interest	(140,000,000)						(140,000,000)
Balance at Dec. 31, 2015	$ 33,725,000,000	$ 10,000,000	$ 29,000,000	$ 37,125,000,000	$ 56,000,000	$ (3,390,000,000)	$ (105,000,000)
Balance (in shares) at Dec. 31, 2015	953	953