EQUITY (Changes in Equity) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended						9 Months Ended
	Jan. 01, 2019	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Common Stock, Dividends, Per Share, Declared		$ 0.45	$ 0.45	$ 0.45	$ 0.41	$ 0.41	$ 0.41
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 5,900.0						$ 5,900.0		$ 1,000.0
Stock Repurchase Program, Authorized Amount		5,000.0						5,000.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Value, Issued, Balance at Beginning of Period				$ 292.0				292.0
Common Stock, Value, Issued, Balance at End of Period		292.0						292.0
Capital in Excess of Par Value of Stock, Balance at Beginning of Period				43,709.0				43,709.0
Capital in Excess of Par Value of Stock, Balance at End of Period		44,435.0						44,435.0
Accumulated Other Comprehensive Loss, Balance at Beginning of Period				(1,520.0)				(1,520.0)
Other Comprehensive (Loss)/Income		(143.0)			$ 1,158.0			(179.0)	$ 1,299.0
Accumulated Other Comprehensive Loss, Balance at End of Period		(1,699.0)						(1,699.0)
Retained Earnings, Balance at Beginning of Period				$ 34,474.0				34,474.0
Net (Loss)/Earnings Attributable to BMS		1,872.0			$ 1,353.0			1,012.0	4,495.0
Retained Earnings, Balance at End of Period		$ 32,414.0						$ 32,414.0
Stock repurchase program, Shares		0.0	16.0	1.0	6.5			1.4
Cost of Treasury Stock, Balance at Beginning of Period				$ (25,357.0)				$ (25,357.0)
Stock Repurchased During Period, Value				(81.0)	$ (300.0)			(81.0)
Cost of Treasury Stock, Balance at End of Period		$ (25,284.0)						(25,284.0)
Noncontrolling interest				$ 100.0				100.0
Noncontrolling Interest		(6.0)			(13.0)			(20.0)	$ (25.0)
Noncontrolling interest		$ 72.0						$ 72.0
2019 ASR [Member]
Stock Repurchase Program, Authorized Amount										$ 7,000.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock repurchase program, Shares		16.0		99.0
Stock Repurchased During Period, Value		$ 0.0	$ (1,400.0)		$ (300.0)
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares Issued, Balance at Beginning of Period	2,208.0	2,923.0	2,923.0	2,923.0	2,208.0	2,208.0	2,208.0	2,923.0	2,208.0
Common Stock, Shares Issued, Balance at End of Period	2,208.0	2,923.0	2,923.0	2,923.0	2,208.0	2,208.0	2,208.0	2,923.0	2,208.0
Common Stock, Value, Issued, Balance at Beginning of Period	$ 221.0	$ 292.0	$ 292.0	$ 292.0	$ 221.0	$ 221.0	$ 221.0	$ 292.0	$ 221.0
Common Stock, Value, Issued, Balance at End of Period	221.0	292.0	292.0	292.0	221.0	221.0	221.0	292.0	221.0
Capital in Excess of Par Value of Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Capital in Excess of Par Value of Stock, Balance at Beginning of Period	2,081.0	44,444.0	43,254.0	43,709.0	2,150.0	2,103.0	2,081.0	43,709.0	2,081.0
Treasury Stock, Value, Acquired, Cost Method		0.0	1,400.0
Stock compensation		(9.0)	(210.0)	(455.0)	56.0	47.0	22.0
Capital in Excess of Par Value of Stock, Balance at End of Period	2,081.0	44,435.0	44,444.0	43,254.0	2,206.0	2,150.0	2,103.0	44,435.0	2,206.0
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accumulated Other Comprehensive Loss, Balance at Beginning of Period	(2,762.0)	(1,556.0)	(1,549.0)	(1,520.0)	(2,621.0)	(2,644.0)	(2,762.0)	(1,520.0)	(2,762.0)
Other Comprehensive (Loss)/Income		(143.0)	(7.0)	(29.0)	1,158.0	23.0	118.0
Accumulated Other Comprehensive Loss, Balance at End of Period	(2,762.0)	(1,699.0)	(1,556.0)	(1,549.0)	(1,463.0)	(2,621.0)	(2,644.0)	(1,699.0)	(1,463.0)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retained Earnings, Balance at Beginning of Period	34,065.0	31,565.0	32,671.0	34,474.0	35,870.0	35,109.0	34,065.0	34,474.0	34,065.0
Net (Loss)/Earnings Attributable to BMS		1,872.0	(85.0)	(775.0)	1,353.0	1,432.0	1,710.0
Cash dividends declared		(1,023.0)	(1,021.0)	(1,028.0)	(668.0)	(671.0)	(671.0)
Retained Earnings, Balance at End of Period	$ 34,070.0	$ 32,414.0	$ 31,565.0	$ 32,671.0	$ 36,555.0	$ 35,870.0	$ 35,109.0	$ 32,414.0	$ 36,555.0
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury Stock, Shares, Balance at Beginning of Period	576.0	669.0	660.0	672.0	572.0	572.0	576.0	672.0	576.0
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation		(6.0)	(7.0)	(13.0)		0.0	(4.0)
Treasury Stock, Shares, Balance at End of Period	576.0	663.0	669.0	660.0	579.0	572.0	572.0	663.0	579.0
Cost of Treasury Stock, Balance at Beginning of Period	$ (19,574.0)	$ (25,651.0)	$ (24,757.0)	$ (25,357.0)	$ (19,571.0)	$ (19,571.0)	$ (19,574.0)	$ (25,357.0)	$ (19,574.0)
Employee stock compensation plans, Cost		367.0	506.0	681.0		0.0	3.0
Cost of Treasury Stock, Balance at End of Period	(19,574.0)	(25,284.0)	(25,651.0)	(24,757.0)	(19,871.0)	(19,571.0)	(19,571.0)	(25,284.0)	(19,871.0)
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling interest	96.0	66.0	66.0	100.0	102.0	99.0	96.0	100.0	96.0
Noncontrolling Interest		6.0	5.0	9.0	13.0	7.0	5.0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders		0.0	(5.0)	(43.0)	(9.0)	(4.0)	(2.0)
Noncontrolling interest	96.0	$ 72.0	$ 66.0	$ 66.0	$ 106.0	$ 102.0	$ 99.0	$ 72.0	$ 106.0
Accounting Standards Update 2016-02 [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of an accounting change on retained earnings	$ 5.0