Other Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Legal and regulatory matters (Note 13)	$ 20	$ 114
Pension and other post-employment benefits (Note 11)	11	11
Income tax contingencies (Note 12)	11	8
Liability to deliver MSRs (Note 16)	2	0
Derivatives (Note 5)	0	18
Other	3	6
Total	$ 47	$ 157