ALLIANCES - Financial Information Pertaining to Alliances (2seventy bio) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total Revenues		$ 46,159	$ 46,385	$ 42,518
Cost of products sold	[1]	10,137	9,940	11,773
Upfront payment related to the collaboration agreement				200
Net product sales
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total Revenues		44,671	45,055	41,321
Alliance revenues
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total Revenues		12,743	11,556	9,979
Cost of products sold		5,768	5,227	4,485
Alliance revenues | Net product sales
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total Revenues		12,001	10,840	$ 9,364
2seventy bio | Alliance revenues
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Cost of products sold		49	42
2seventy bio | Alliance revenues | Net product sales
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total Revenues		$ 297	$ 158

[1] Excludes amortization of acquired intangible assets.