CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 3,460	$ 4,947	$ 975
Other Comprehensive Income (Loss), net of taxes and reclassifications to earnings [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	(32)	70	(57)
Pension and postretirement benefits	1,203	53	214
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	36	(25)	39
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	35	(254)	18
Other Comprehensive Income (Loss), Net of Tax	1,242	(156)	214
Comprehensive Income	4,702	4,791	1,189
Comprehensive Income Attributable to Noncontrolling Interest	21	27	(32)
Comprehensive Income Attributable to BMS	$ 4,681	$ 4,764	$ 1,221