Investments (Leveraged and Direct Financing Leases - Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Lessor, Lease, Description [Line Items]
Loans and Leases Receivable, Other Information	The payment periods for leveraged leases generally range from one to 15 years but in certain circumstances can be over 25 years, while the payment periods for direct financing leases generally range from one to 25 years but in certain circumstances can be over 25 years
Leveraged Leases, Net Investment in Leveraged Leases Disclosure, Deferred Taxes Arising from Leveraged Leases	$ 510	$ 519
Minimum | Performing
Lessor, Lease, Description [Line Items]
Loans and Leases Receivable, Ratio of Performing Loans to All Loans	99.00%	99.00%