Businesses Held for Sale and Discontinued Operations (Rollforward of the Reserve) (Details) - WMC - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Financial Information For Discontinued Operations [Line Items]
Reserve, beginning of period	$ 860	$ 825	$ 875	$ 809	$ 809
Provision	0	28	84	46
Claim resolutions	(195)	(21)	(294)	(23)
Reserve, end of period	665	$ 832	665	$ 832	875
Pending claims, beginning of period			2,887
New claims			5,628		8,047
Pending claims, end of period	1,266		1,266		$ 2,887
Claims Relating To Alleged Breaches Of Representations That Are Beyond Applicable Statute Of Llimitations	$ 110		$ 110