Fair Value Measurements (Details 3) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Components of Mortgage loans held for sale
Mortgage loans held for sale	$ 922	$ 743
First mortgages
Components of Mortgage loans held for sale
Mortgage loans held for sale	879	704
First mortgages, Conforming
Components of Mortgage loans held for sale
Mortgage loans held for sale	720	616
First mortgages, Non-conforming
Components of Mortgage loans held for sale
Mortgage loans held for sale	159	88
Second lien
Components of Mortgage loans held for sale
Mortgage loans held for sale	4	4
Scratch and Dent
Components of Mortgage loans held for sale
Mortgage loans held for sale	38	35
Other
Components of Mortgage loans held for sale
Mortgage loans held for sale	$ 1	$ 0