XML 93 R69.htm IDEA: XBRL DOCUMENT v3.22.0.1
Pensions and Other Postretirement Benefits - Narrative (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2021
USD ($)
investment_firm
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan's accumulated benefit obligation $ 2,600 $ 2,600  
Unfunded pension plans projected benefit obligation 358 359  
Unfunded pension plans accumulated benefit obligations $ 332 330  
Number of investment firms | investment_firm 11    
Multiemployer plan, contributions by employer $ 21 22 $ 31
Defined contribution plan, cost 23 21 $ 22
Level 2      
Defined Benefit Plan Disclosure [Line Items]      
Trust-owned life insurance fair value $ 173 $ 165  
Minimum      
Defined Benefit Plan Disclosure [Line Items]      
Pension plan assets target allocation for equity 50.00%    
Maximum      
Defined Benefit Plan Disclosure [Line Items]      
Pension plan assets target allocation for equity 75.00%    
Debt securities      
Defined Benefit Plan Disclosure [Line Items]      
Weighted average asset allocation, by asset category 35.00% 32.00%  
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Estimated net loss for defined pension plans amortized from AOCI into net periodic cost $ 48    
Assumed increases in per capita cost of covered health care benefits 6.50%    
Ultimate health care cost trend rate 5.00%    
Pension plan assets target allocation for equity 75.00%    
Assumed rate of return on pension plan assets 8.00%    
Expected contribution for the next fiscal year $ 20    
Other Postretirement Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, future amortization of prior service cost (credit) 25    
Expected contribution for the next fiscal year $ 34    
Other Postretirement Benefits | Defined Benefit Plan, Equity Securities      
Defined Benefit Plan Disclosure [Line Items]      
Weighted average asset allocation, by asset category 65.00% 68.00%