Variable Interest Entities ("VIE's") (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Carrying Amounts of our Investments in LPs and LLCs, As Recognized In Other Investments on our Consolidated Balance Sheets	$ 2,104	$ 2,230
Limited Partnerships and Limited Liability Companies [Member]
Carrying Amounts of our Investments in LPs and LLCs, As Recognized In Other Investments on our Consolidated Balance Sheets	1,300	1,300
Carrying Amount Of Investments In Qualified Affordable Housing Projects	$ 35	$ 37