Investments (Components of Leveraged and and Direct Financing Leases) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Rental Receivables, Net	$ 711	$ 715
Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Residual Value of Leased Assets	807	807
Investment In Leveraged Leases	1,518	1,522
Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Deferred Income	(403)	(414)
Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Investment in Leveraged Leases, Net	1,115	1,108
Direct Financing Lease, Lease Receivable	1,951	1,855
Direct Financing Lease, Unguaranteed Residual Asset	42	42
Investment In Direct Financing Leases	1,993	1,897
Direct Financing Lease, Deferred Selling Profit	(716)	(705)
Direct Financing Lease, Net Investment in Lease	1,277	$ 1,192
Capital Leases, Future Minimum Payments Receivable, Next Twelve Months	84
Capital Leases, Future Minimum Payments, Receivable in Two Years	106
Capital Leases, Future Minimum Payments, Receivable in Three Years	105
Capital Leases, Future Minimum Payments, Receivable in Four Years	109
Capital Leases, Future Minimum Payments, Receivable in Five Years	102
Capital Leases, Future Minimum Payments, Receivable Thereafter	1,400
Capital Leases, Future Minimum Payments Receivable	$ 2,000