Annual report pursuant to Section 13 and 15(d)

BENEFIT PLANS - Asset Allocation Ranges and Actual Allocation, USRIP) (Details)

v3.20.4
BENEFIT PLANS - Asset Allocation Ranges and Actual Allocation, USRIP) (Details) - Other Benefits - U.S.
Dec. 31, 2020
Dec. 31, 2019
U.S. Equity    
Defined Benefit Plan Disclosure [Line Items]    
Actual 6.60% 11.50%
International Equity    
Defined Benefit Plan Disclosure [Line Items]    
Actual 5.80% 12.70%
Private Equity    
Defined Benefit Plan Disclosure [Line Items]    
Actual 1.70% 2.30%
Hedge Funds    
Defined Benefit Plan Disclosure [Line Items]    
Actual 2.60% 6.60%
Real Assets    
Defined Benefit Plan Disclosure [Line Items]    
Actual 2.80% 3.40%
Fixed Income    
Defined Benefit Plan Disclosure [Line Items]    
Actual 76.70% 61.80%
Cash    
Defined Benefit Plan Disclosure [Line Items]    
Actual 3.80% 1.70%
Minimum | U.S. Equity    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.00% 0.05%
Minimum | International Equity    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.00% 0.05%
Minimum | Private Equity    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.00% 0.00%
Minimum | Hedge Funds    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.00% 0.00%
Minimum | Real Assets    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.00% 0.00%
Minimum | Fixed Income    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.65% 0.35%
Minimum | Cash    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.00% 0.00%
Maximum | U.S. Equity    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.20% 0.35%
Maximum | International Equity    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.10% 0.20%
Maximum | Private Equity    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.10% 0.10%
Maximum | Hedge Funds    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.10% 0.10%
Maximum | Real Assets    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.10% 0.10%
Maximum | Fixed Income    
Defined Benefit Plan Disclosure [Line Items]    
Range 1.00% 0.65%
Maximum | Cash    
Defined Benefit Plan Disclosure [Line Items]    
Range 0.15% 0.15%