Financing Receivables (Schedule Of Lease Receivables, Net Of Nonrecourse Debt, Associated With Leveraged Lease Portfolio Based On Counterparty Credit Rating) (Detail) - Energy Holdings [Member] - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	$ 274	$ 299
Standard & Poor's, AA Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	8
Standard & Poor's, A- Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	51
Standard & Poor's, BBB plus - BBB - Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	178
Standard & Poor's, BB Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	$ 37