Accounting Policies and Supplemental Disclosures - Acquisition Activity (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Feb. 22, 2023	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Business Acquisition [Line Items]
Cash consideration		$ 3,513	$ 6,341	$ 5,488	$ 7,696
Goodwill		$ 22,749		$ 22,749		$ 20,288
1Life Healthcare
Business Acquisition [Line Items]
Cash consideration	$ 3,500
Intangible assets	1,300
Goodwill	$ 2,500