Consolidated Statements of Changes in Shareholders' Equity (USD $) In Millions, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Net Unrealized Gains (Losses) on Investments [Member]	Foreign Currency Translation Losses [Member]
Balance at Dec. 31, 2011	$ 28,292	$ 10	$ 0	$ 27,821	$ 476	$ (15)
Balance (in shares) at Dec. 31, 2011		1,039
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to UnitedHealth Group common shareholders	5,526			5,526
Other comprehensive income (loss)	(23)				40	(63)
Issuances of common stock, and related tax effects (in shares)		37
Issuances of common stock, and related tax effects	704	0	704
Share-based compensation, and related tax benefits	594		594
Common stock repurchases (in shares)		(57)
Common stock repurchases	(3,084)	0	(1,221)	(1,863)
Acquisitions of noncontrolling interests	(11)		(11)
Cash dividends paid on common shares	(820)			(820)
Balance at Dec. 31, 2012	31,178	10	66	30,664	516	(78)
Balance (in shares) at Dec. 31, 2012		1,019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to UnitedHealth Group common shareholders	5,625			5,625
Other comprehensive income (loss)	(1,346)				(462)	(884)
Issuances of common stock, and related tax effects (in shares)		17
Issuances of common stock, and related tax effects	431	0	431
Share-based compensation, and related tax benefits	406		406
Common stock repurchases (in shares)		(48)
Common stock repurchases	(3,170)	0	(984)	(2,186)
Acquisitions of noncontrolling interests	(1,417)
Acquisitions of noncontrolling interests and related tax effects	81		81
Cash dividends paid on common shares	(1,056)			(1,056)
Balance at Dec. 31, 2013	32,149	10	0	33,047	54	(962)
Balance (in shares) at Dec. 31, 2013	988	988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to UnitedHealth Group common shareholders	5,619			5,619
Other comprehensive income (loss)	(484)				169	(653)
Issuances of common stock, and related tax effects (in shares)		15
Issuances of common stock, and related tax effects	146	0	146
Share-based compensation, and related tax benefits	394		394
Common stock repurchases (in shares)	(49)	(49)
Common stock repurchases	(4,008)	0	(540)	(3,468)
Acquisitions of noncontrolling interests	0
Cash dividends paid on common shares	(1,362)			(1,362)
Balance at Dec. 31, 2014	$ 32,454	$ 10	$ 0	$ 33,836	$ 223	$ (1,615)
Balance (in shares) at Dec. 31, 2014	954	954