Intangible Assets and Goodwill (Changes in Carrying Amount of Goodwill as Allocated to Reportable Segments) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015
Goodwill [Line Items]
Beginning balance	$ 1,227	[1]	$ 1,227
Goodwill acquired and other changes during the period
Ending balance	1,227		1,227	[1]
Investor Services [Member]
Goodwill [Line Items]
Beginning balance	1,096		1,127
Goodwill acquired and other changes during the period			(31)
Ending balance	1,096		1,096
Advisor Services [Member]
Goodwill [Line Items]
Beginning balance	131		100
Goodwill acquired and other changes during the period			31
Ending balance	$ 131		$ 131

[1] Adjusted for the retrospective adoption of ASU 2015-03. See New Accounting Standards in Note 2 for additional information.