Finance Assets, net (Schedule of Credit Quality of Investments in Finance Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Gross investments in finance leases	$ 922	$ 1,060
Finance Leases Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross investments in finance leases	922	1,060
Finance Leases Financing Receivable [Member] | Standard & Poor's AAA To A Minus [Member] | Moodys Aaa to A3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross investments in finance leases	220	218
Finance Leases Financing Receivable [Member] | Standard & Poor's BBB Plus To BBB Minus [Member] | Moodys Baa1 to Baa3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross investments in finance leases	550	559
Finance Leases Financing Receivable [Member] | Standard & Poor's BB Plus And Lower [Member] | Moodys Ba1 and Lower [Member]
Financing Receivable, Recorded Investment [Line Items]
Gross investments in finance leases	$ 152	$ 283