MEDICARE PART D (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Other current assets	$ 5,710	$ 6,493
Trade accounts payable and accrued expenses	(5,859)	(4,509)
Other long-term assets	4,610	4,379
Other long-term liabilities	(2,149)	(2,383)
Risk Corridor Settlement
Segment Reporting Information [Line Items]
Other current assets	139	363
Trade accounts payable and accrued expenses	(52)	(68)
Net current asset (liability)	87	295
Other long-term assets	310	5
Other long-term liabilities	(221)	(194)
Net long-term asset (liability)	89	(189)
Total net asset (liability)	176	106
CMS Subsidies/ Discounts
Segment Reporting Information [Line Items]
Other current assets	997	1,894
Trade accounts payable and accrued expenses	(2,046)	(466)
Net current asset (liability)	(1,049)	1,428
Other long-term assets	0	0
Other long-term liabilities	0	0
Net long-term asset (liability)	0	0
Total net asset (liability)	$ (1,049)	$ 1,428