Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS AND RISK MANAGEMENT - Additional Information (Detail)

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DERIVATIVE INSTRUMENTS AND RISK MANAGEMENT - Additional Information (Detail) - USD ($)
 3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2020
Dec. 31, 2019
Derivative [Line Items]      
Collateral received under contractual provisions $ 319,000,000 $ 319,000,000 $ 495,000,000
Derivative net liability position 0 0 0
Commodity Asset $ 0 0 0
Pre-tax losses related to cash flow hedges that are currently deferred in AOCI and are expected to be reclassified to income within twelve months   $ 139,000,000  
Maximum term over hedging exposures to the variability of cash flow   12 years  
Derivative Instrument Recognition Period 10 years    
Cash Collateral from Counterparties [Abstract] $ 0 $ 0 0
Quoted Prices in Active Markets for Identical Assets (Level 1)      
Derivative [Line Items]      
Derivatives classified as Level 1 or Level 3 0 0 0
Significant Other Observable Inputs (Level 2)      
Derivative [Line Items]      
Liability Derivatives 38,000,000 38,000,000 37,000,000
Derivative Asset, Fair Value, Gross Asset 312,000,000 312,000,000 432,000,000
Significant Unobservable Inputs (Level 3)      
Derivative [Line Items]      
Derivatives classified as Level 1 or Level 3 0 0 $ 0
Long-term debt and finance leases | Not Designated as Hedging Instrument | Fair Value      
Derivative [Line Items]      
Liability Derivatives $ 9,000,000 $ 9,000,000