Goodwill and Other Intangibles - Goodwill (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Goodwill [Roll Forward]
Balance, beginning of the period			$ 79,552
Goodwill impairment	$ (431)	$ 0	(431)	$ 0
Balance, end of the period	79,121		79,121
Health Care Benefits
Goodwill [Roll Forward]
Balance, beginning of the period			45,130
Goodwill impairment			0
Balance, end of the period	45,130		45,130
Pharmacy Services
Goodwill [Roll Forward]
Balance, beginning of the period			23,615
Goodwill impairment			0
Balance, end of the period	23,615		23,615
Retail/ LTC
Goodwill [Roll Forward]
Balance, beginning of the period			10,807
Goodwill impairment			(431)
Balance, end of the period	$ 10,376		$ 10,376