Related Party Transactions (Related Party Transactions) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
All Services and Transactions Except Broker Dealer Activities [Member]
Related Party Transaction [Line Items]
Due from Related Parties	$ 93		$ 93		$ 2,839
Due to Related Parties	0		0		2,675
Revenue from Related Parties	95	$ (11)	155	$ (121)
Related Party Transaction, Expenses from Transactions with Related Party	390	259	739	668
Broker Dealer Activities [Member]
Related Party Transaction [Line Items]
Due from Related Parties	18		18		$ 19
Revenue from Related Parties	55	56	166	167
Related Party Transaction, Expenses from Transactions with Related Party	$ 214	$ 157	$ 540	$ 477

For an unclassified balance sheet, amounts due from related parties including affiliates, employees, joint ventures, officers and stockholders, immediate families thereof, and pension funds.

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Carrying amount as of the balance sheet date of obligations due all related parties.

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