Quarterly Results (Unaudited - Narratives) (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Discrete income tax benefit	$ 135		$ 564
Losses on sales and markdowns of limited partnership investments	60
Severance costs		$ 155
Start date of current common stock dividend per share declared				Jul. 20, 2016
Institutional Securities
Discrete income tax benefit				$ 68	$ 564	$ 839
Severance costs		125
Wealth Management
Discrete income tax benefit						$ 1,390
Brokerage service reporting expenses	$ 70
Severance costs		20
Investment Management
Severance costs		$ 10