Condensed Consolidated Statements of Changes in Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Net Unrealized (Losses) Gains on Investments [Member]	Foreign Currency Translation [Member]	Nonredeemable Noncontrolling Interests [Member]
Balance at Dec. 31, 2017	$ 49,833	$ 10	$ 1,703	$ 48,730	$ (13)	$ (2,654)	$ 2,057
Balance (in shares) at Dec. 31, 2017		969
Adjustment to adopt ASU at Dec. 31, 2017	0			(24)	24
Net earnings attributable to UnitedHealth Group common shareholders	5,758			5,758
Net earnings attributable to nonredeemable noncontrolling interest							112
Net Earnings, Including Portion Attributable to Nonredeemable Noncontrolling Interest	5,870
Other comprehensive income (loss)	(1,437)				(367)	(1,070)
Issuances of common stock, and related tax effects (in shares)		7
Issuances of common stock, and related tax effects	522	$ 0	522
Share-based compensation	347		347
Common share repurchases (in shares)		(14)
Common share repurchases	(3,150)	$ 0	(2,637)	(513)
Cash dividends paid on common shares	(1,588)			(1,588)
Redeemable noncontrolling interests fair value and other adjustments	65		65
Acquisition and other adjustments of nonredeemable noncontrolling interests	416						416
Distribution to nonredeemable noncontrolling interests	(95)						(95)
Balance at Jun. 30, 2018	50,783	$ 10	0	52,363	(356)	(3,724)	2,490
Balance (in shares) at Jun. 30, 2018		962
Balance at Mar. 31, 2018	50,036	$ 10	0	50,494	(296)	(2,655)	2,483
Balance (in shares) at Mar. 31, 2018		962
Net earnings attributable to UnitedHealth Group common shareholders	2,922			2,922
Net earnings attributable to nonredeemable noncontrolling interest							59
Net Earnings, Including Portion Attributable to Nonredeemable Noncontrolling Interest	2,981
Other comprehensive income (loss)	(1,129)				(60)	(1,069)
Issuances of common stock, and related tax effects (in shares)		2
Issuances of common stock, and related tax effects	107	$ 0	107
Share-based compensation	141		141
Common share repurchases (in shares)		(2)
Common share repurchases	(500)	$ 0	(313)	(187)
Cash dividends paid on common shares	(866)			(866)
Redeemable noncontrolling interests fair value and other adjustments	65		65
Acquisition and other adjustments of nonredeemable noncontrolling interests	(7)						(7)
Distribution to nonredeemable noncontrolling interests	(45)						(45)
Balance at Jun. 30, 2018	50,783	$ 10	0	52,363	(356)	(3,724)	2,490
Balance (in shares) at Jun. 30, 2018		962
Balance at Dec. 31, 2018	$ 54,319	$ 10	0	55,846	(264)	(3,896)	2,623
Balance (in shares) at Dec. 31, 2018	960	960
Adjustment to adopt ASU at Dec. 31, 2018	$ (18)			(13)			(5)
Net earnings attributable to UnitedHealth Group common shareholders	6,760			6,760
Net earnings attributable to nonredeemable noncontrolling interest							114
Net Earnings, Including Portion Attributable to Nonredeemable Noncontrolling Interest	6,874
Other comprehensive income (loss)	887				780	107
Issuances of common stock, and related tax effects (in shares)		6
Issuances of common stock, and related tax effects	161	$ 0	161
Share-based compensation	391		391
Common share repurchases (in shares)		(18)
Common share repurchases	(4,501)	$ (1)	(158)	(4,342)
Cash dividends paid on common shares	(1,884)			(1,884)
Redeemable noncontrolling interests fair value and other adjustments	(285)		(285)
Acquisition and other adjustments of nonredeemable noncontrolling interests	55		(109)				164
Distribution to nonredeemable noncontrolling interests	(145)						(145)
Balance at Jun. 30, 2019	$ 55,854	$ 9	0	56,367	516	(3,789)	2,751
Balance (in shares) at Jun. 30, 2019	948	948
Balance at Mar. 31, 2019	$ 54,451	$ 10	0	55,472	140	(3,898)	2,727
Balance (in shares) at Mar. 31, 2019		953
Net earnings attributable to UnitedHealth Group common shareholders	3,293			3,293
Net earnings attributable to nonredeemable noncontrolling interest							54
Net Earnings, Including Portion Attributable to Nonredeemable Noncontrolling Interest	3,347
Other comprehensive income (loss)	485				376	109
Issuances of common stock, and related tax effects (in shares)		1
Issuances of common stock, and related tax effects	105	$ 0	105
Share-based compensation	152		152
Common share repurchases (in shares)		(6)
Common share repurchases	(1,499)	$ (1)	(124)	(1,374)
Cash dividends paid on common shares	(1,024)			(1,024)
Redeemable noncontrolling interests fair value and other adjustments	(133)		(133)
Acquisition and other adjustments of nonredeemable noncontrolling interests	32						32
Distribution to nonredeemable noncontrolling interests	(62)						(62)
Balance at Jun. 30, 2019	$ 55,854	$ 9	$ 0	$ 56,367	$ 516	$ (3,789)	$ 2,751
Balance (in shares) at Jun. 30, 2019	948	948