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, 2018	Dec. 31, 2017
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	$ 545	$ 546
Standard & Poor's, AA Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	14
Standard & Poor's, BBB plus - BBB - Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	316
Standard & Poor's, BB- Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	133
Standard & Poor's, CCC minus Rating [Member]
Schedule of Financial Receivables [Line Items]
Lease Receivables (net of Non-Recourse Debt)	$ 82