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, 2018	$ 54,319	$ 10	$ 0	$ 55,846	$ (264)	$ (3,896)	$ 2,623
Balance (Adjustment to adopt ASU 2016-02) at Dec. 31, 2018	(18)			(13)			(5)
Balance (in shares) at Dec. 31, 2018		960
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
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
Balance at Dec. 31, 2019	60,436	$ 9	7	61,178	589	(4,167)	2,820
Balance (Adjustment to Adopt ASU 2016-13) at Dec. 31, 2019	$ (28)			(28)
Balance (in shares) at Dec. 31, 2019	948	948
Net earnings attributable to UnitedHealth Group common shareholders	$ 10,019			10,019
Net earnings attributable to nonredeemable noncontrolling interest							97
Net Earnings, Including Portion Attributable to Nonredeemable Noncontrolling Interest	10,116
Other comprehensive income (loss)	(972)				572	(1,544)
Issuances of common stock, and related tax effects (in shares)		8
Issuances of common stock, and related tax effects	608	$ 1	607
Share-based compensation	378		378
Common share repurchases (in shares)		(6)
Common share repurchases	(1,691)	$ 0	(510)	(1,181)
Cash dividends paid on common shares	(2,212)			(2,212)
Redeemable noncontrolling interests fair value and other adjustments	(94)		(94)
Acquisition and other adjustments of nonredeemable noncontrolling interests	50						50
Distribution to nonredeemable noncontrolling interests	(76)						(76)
Balance at Jun. 30, 2020	$ 66,515	$ 10	388	67,776	1,161	(5,711)	2,891
Balance (in shares) at Jun. 30, 2020	950	950
Balance at Mar. 31, 2020	$ 59,863	$ 10	0	62,327	306	(5,666)	2,886
Balance (in shares) at Mar. 31, 2020		947
Net earnings attributable to UnitedHealth Group common shareholders	6,637			6,637
Net earnings attributable to nonredeemable noncontrolling interest							38
Net Earnings, Including Portion Attributable to Nonredeemable Noncontrolling Interest	6,675
Other comprehensive income (loss)	810				855	(45)
Issuances of common stock, and related tax effects (in shares)		3
Issuances of common stock, and related tax effects	287	$ 0	287
Share-based compensation	144		144
Common share repurchases (in shares)		0
Common share repurchases	0	$ 0	0	0
Cash dividends paid on common shares	(1,188)			(1,188)
Redeemable noncontrolling interests fair value and other adjustments	(43)		(43)
Distribution to nonredeemable noncontrolling interests	(33)						(33)
Balance at Jun. 30, 2020	$ 66,515	$ 10	$ 388	$ 67,776	$ 1,161	$ (5,711)	$ 2,891
Balance (in shares) at Jun. 30, 2020	950	950