Business, Basis of Presentation and Significant Accounting Policies - Adoption of Accounting Pronouncements (Details) $ in Millions		12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2017 USD ($) segments	Dec. 31, 2016 USD ($)	Jan. 01, 2017 USD ($)	Jan. 01, 2016 USD ($)
New Accounting Pronouncement, Early Adoption [Line Items]
Total assets		$ 222,532	$ 214,585
Limited partnerships/corporations		784	536
Other assets		15,394	15,756
Liabilities		211,493	200,617
Collateralized loan obligations notes, at fair value using the fair value option		1,047	1,967
Other liabilities		658	528
Noncontrolling interest		1,030	973
Appropriated-consolidated investment entities		$ 0	0
Number of operating segments | segments		4
Accounting Standards Update 2016-09
New Accounting Pronouncement, Early Adoption [Line Items]
ASU 2016-09 Deferred tax asset change				$ 15
ASU 2016-09 Share-based compensation cash flow reclass			$ 5
Cumulative-Effect Adjustment, Deconsolidation of Variable Interest Entity [Member]
New Accounting Pronouncement, Early Adoption [Line Items]
Total assets					$ 7,500
Limited partnerships/corporations					2,500
Cash and cash equivalents					300
Corporate loans, at fair value using the fair value option					4,600
Other assets					100
Liabilities					5,900
Collateralized loan obligations notes, at fair value using the fair value option					4,600
Other liabilities					1,300
Noncontrolling interest					1,600
Appropriated-consolidated investment entities					9
Accounting Standards Update 2014-13
New Accounting Pronouncement, Early Adoption [Line Items]
Collateralized loan obligations notes, at fair value using the fair value option					18
Appropriated-consolidated investment entities					$ (18)
Scenario, Forecast | Accounting Standards Update 2014-09
New Accounting Pronouncement, Early Adoption [Line Items]
ASU 2014-09 Cumulative Effect on Retained Earnings, Net of Tax	$ 80