XML 27 R73.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Regulatory Assets and Liabilities Schedule of Regulatory Assets and Liabilities (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Regulatory Assets [Line Items]    
Regulatory Assets $ 500 $ 462
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 438  
Regulatory Liabilities 1,421 1,391
Regulatory Assets Earning a Rate of Return at the Approved Rate 1,405  
Removal Costs [Member]    
Regulatory Assets [Line Items]    
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 0  
Regulatory Liabilities 1,021 979
Deferred Income Tax Charge [Member]    
Regulatory Assets [Line Items]    
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 0  
Regulatory Liabilities 260 267
Asset Retirement Obligation Costs [Member]    
Regulatory Assets [Line Items]    
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 0  
Regulatory Liabilities $ 54 53
Revenue Subject to Refund [Member]    
Regulatory Assets [Line Items]    
Regulatory Current Asset, End Date for Recovery 2020  
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided $ 0  
Regulatory Liabilities 23 45
Other Regulatory Assets (Liabilities) [Member]    
Regulatory Assets [Line Items]    
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 16  
Regulatory Liabilities 63 47
Regulatory Assets Earning a Rate of Return at the Approved Rate 47  
Other Regulatory Assets Earning a Return [Member]    
Regulatory Assets [Line Items]    
Regulatory Assets 62  
Earning a return [Member]    
Regulatory Assets [Line Items]    
Regulatory Assets $ 62  
Deferred Derivative Gain (Loss) [Member]    
Regulatory Assets [Line Items]    
Regulatory Current Asset, End Date for Recovery 2035  
Regulatory Assets $ 0 131
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 95  
Pension and Other Postretirement Plans Costs [Member]    
Regulatory Assets [Line Items]    
Regulatory Assets 0 222
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided $ 213  
Loss on Reacquired Debt [Member]    
Regulatory Assets [Line Items]    
Regulatory Current Asset, End Date for Recovery 2049  
Regulatory Assets $ 0 16
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided $ 26  
Environmental Restoration Costs [Member]    
Regulatory Assets [Line Items]    
Regulatory Current Asset, End Date for Recovery 2059  
Regulatory Assets $ 0  
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided 94 26
Other Regulatory Assets (Liabilities) [Member]    
Regulatory Assets [Line Items]    
Regulatory Assets 72 $ 67
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided $ 10