PENSION AND POSTRETIREMENT BENEFIT PLANS (Fair Value Disclosures) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 2,934	$ 6,461
Equity Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	87	124
Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	548	477
Fixed Income Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	769	606
Corporate Debt Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	764	3,865
U.S. Treasury and Agency Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	168	553
Short-Term Investment Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	55
Insurance Contracts [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	128	134
Cash and Cash Equivalents [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	24	311
Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	144	124
Fair Value Level 1 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	115	437
Fair Value Level 1 [Member] | Equity Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	87	124
Fair Value Level 1 [Member] | Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	4	2
Fair Value Level 1 [Member] | Fixed Income Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 1 [Member] | Corporate Debt Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 1 [Member] | U.S. Treasury and Agency Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 1 [Member] | Short-Term Investment Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 1 [Member] | Insurance Contracts [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 1 [Member] | Cash and Cash Equivalents [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	24	311
Fair Value Level 1 [Member] | Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 2 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2,356	5,659
Fair Value Level 2 [Member] | Equity Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 2 [Member] | Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	544	475
Fair Value Level 2 [Member] | Fixed Income Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	769	606
Fair Value Level 2 [Member] | Corporate Debt Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	764	3,865
Fair Value Level 2 [Member] | U.S. Treasury and Agency Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	168	553
Fair Value Level 2 [Member] | Short-Term Investment Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	55
Fair Value Level 2 [Member] | Insurance Contracts [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 2 [Member] | Cash and Cash Equivalents [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 2 [Member] | Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	111	105
Fair Value Level 3 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	161	153
Fair Value Level 3 [Member] | Equity Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | Equity Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | Fixed Income Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | Corporate Debt Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | U.S. Treasury and Agency Securities [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | Short-Term Investment Funds [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | Insurance Contracts [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	128	134
Fair Value Level 3 [Member] | Cash and Cash Equivalents [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	0
Fair Value Level 3 [Member] | Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	33	19
Fair Value, Inputs, Level 1, 2 and 3 [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2,632	6,249
Fair Value Measured at Net Asset Value Per Share [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	302	212
Fair Value Measured at Net Asset Value Per Share [Member] | Other[Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	301	91
Fair Value Measured at Net Asset Value Per Share [Member] | Venture Capital and Limited Partnerships [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1	121
Pension Plans, Defined Benefit [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Funded Status	(404)	163
Defined Benefit Plan, Plan Assets, Amount	2,536	$ 6,129	$ 6,749
Bristol-Myers Squibb Retirement Income Plan [Member] | Pension Plans, Defined Benefit [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Funded Status	$ 424