Schedule I Condensed Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 10,985	$ 10,866	$ 11,981	$ 10,430
Total current assets	42,634	38,692
Other assets	9,334	4,326
Total assets	173,889	152,221	139,058
Current liabilities:
Accounts payable and accrued liabilities	19,005	16,705
Commercial paper and current maturities of long-term debt	3,870	1,973
Total current liabilities	61,782	53,209
Long-term debt, less current maturities	36,808	34,581
Other liabilities	10,144	5,730
Total liabilities	111,727	95,994
Commitments and contingencies (Note 4)
Shareholders’ equity:
Preferred stock, $0.001 par value - 10 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.01 par value - 3,000 shares authorized; 948 and 960 issued and outstanding	9	10
Additional paid-in capital	7	0
Retained earnings	61,178	55,846
Accumulated other comprehensive loss	(3,578)	(4,160)
Total liabilities and shareholders’ equity	173,889	152,221
Parent Company [Member]
Current assets:
Cash and cash equivalents	46	434	$ 359	$ 180
Other current assets	787	197
Total current assets	833	631
Equity in net assets of subsidiaries	93,467	83,244
Long-term notes receivable from subsidiaries	5,079	4,461
Other assets	794	972
Total assets	100,173	89,308
Current liabilities:
Accounts payable and accrued liabilities	688	618
Current portion of notes payable to subsidiaries	750	714
Commercial paper and current maturities of long-term debt	3,548	1,744
Total current liabilities	4,986	3,076
Long-term debt, less current maturities	35,926	33,490
Long-term notes payable to subsidiaries	1,314	560
Other liabilities	331	486
Total liabilities	42,557	37,612
Shareholders’ equity:
Preferred stock, $0.001 par value - 10 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.01 par value - 3,000 shares authorized; 948 and 960 issued and outstanding	9	10
Additional paid-in capital	7	0
Retained earnings	61,178	55,846
Accumulated other comprehensive loss	(3,578)	(4,160)
Total UnitedHealth Group shareholders’ equity	57,616	51,696
Total liabilities and shareholders’ equity	$ 100,173	$ 89,308