Financing Receivables (Schedule Of Lease Receivables, Net Of Nonrecourse Debt, Associated With Leveraged Lease Portfolio Based On Counterparty Credit Rating) (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Lease Receivables, Net of Non-Recourse Debt	$ 299	$ 498
Energy Holdings [Member]
Guarantor Obligations [Line Items]
Lease Receivables, Net of Non-Recourse Debt	299
Energy Holdings [Member] | Counterparties' Credit Rating (S&P), AA [Member]
Guarantor Obligations [Line Items]
Lease Receivables, Net of Non-Recourse Debt	9
Energy Holdings [Member] | Standard & Poor's, A- Rating [Member]
Guarantor Obligations [Line Items]
Lease Receivables, Net of Non-Recourse Debt	54
Energy Holdings [Member] | Counterparties' Credit Rating (S&P), BBB plus, BBB, BBB minus [Member]
Guarantor Obligations [Line Items]
Lease Receivables, Net of Non-Recourse Debt	196
Energy Holdings [Member] | Standard & Poor's, BB Rating [Member]
Guarantor Obligations [Line Items]
Lease Receivables, Net of Non-Recourse Debt	$ 40