Financial Risk Management Activities (Schedule Of Derivative Instruments Designated As Cash Flow Hedges) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pre-Tax Gain (Loss) attributed to Cash Flow Hedges Recognized in AOCI on Derivatives (Effective Portion)	$ 0	$ 0	$ (6)
Amount of Pre-Tax Loss Reclassified from AOCL into Income, Effective Portion	(5)	(4)	(14)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	30	11	(4)
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Pre-Tax Gain (Loss) attributed to Cash Flow Hedges Recognized in AOCI on Derivatives (Effective Portion)	0	0	(6)
Amount of Pre-Tax Loss Reclassified from AOCL into Income, Effective Portion	(5)	(4)	(14)
Cash Flow Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	3	3	10
Cash Flow Hedges | Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	$ 3	$ 3	$ 10