Financial Assets And Financial Liabilities (Financial Assets and Liabilities Not Measured at Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 2,597	$ 1,732	$ 1,925
Cash - segregated for regulatory purposes	7,503	6,547	$ 5,624
Securities - segregated for regulatory purposes	15,595	13,685
Securities borrowed	3,331	2,957
Securities purchased under agreements to resell	1,242	2,035
Receivables from customer	27,017	29,821
Receivables from brokers, dealers and clearing organizations	706	823
Interest Receivable	141	116
Other assets	296	292
Short-term borrowings	17	15
Securities loaned	4,037	4,444
Securities sold under agreements to repurchase		1,316
Customers	47,993	47,548
Brokers, dealers and clearing organizations	298	283
Interest Payable	41	22
at Fair Value
Cash and cash equivalents	2,597	1,732
Cash - segregated for regulatory purposes	7,503	6,547
Securities - segregated for regulatory purposes	11,382	9,166
Securities borrowed	3,331	2,957
Securities purchased under agreements to resell	1,242	2,035
Receivables from customer	27,017	29,821
Receivables from brokers, dealers and clearing organizations	706	823
Interest Receivable	141	116
Other assets	6	6
Total financial assets, not measured at fair value	53,925	53,203
Short-term borrowings	17	15
Securities loaned	4,037	4,444
Securities sold under agreements to repurchase		1,316
Customers	47,993	47,548
Brokers, dealers and clearing organizations	298	283
Interest Payable	41	22
Total financial liabilities, not measured at fair value	52,386	53,628
Carrying Value
Cash and cash equivalents	2,597	1,732
Cash - segregated for regulatory purposes	7,503	6,547
Securities - segregated for regulatory purposes	11,382	9,166
Securities borrowed	3,331	2,957
Securities purchased under agreements to resell	1,242	2,035
Receivables from customer	27,017	29,821
Receivables from brokers, dealers and clearing organizations	706	823
Interest Receivable	141	116
Other assets	5	6
Total financial assets, not measured at fair value	53,924	53,203
Short-term borrowings	17	15
Securities loaned	4,037	4,444
Securities sold under agreements to repurchase		1,316
Customers	47,993	47,548
Brokers, dealers and clearing organizations	298	283
Interest Payable	41	22
Total financial liabilities, not measured at fair value	52,386	53,628
Level 1
Cash and cash equivalents	2,597	1,732
Cash - segregated for regulatory purposes	7,503	6,547
Total financial assets, not measured at fair value	10,100	8,279
Short-term borrowings
Securities loaned
Securities sold under agreements to repurchase
Customers
Brokers, dealers and clearing organizations
Interest Payable
Total financial liabilities, not measured at fair value
Level 2
Securities - segregated for regulatory purposes	11,382	9,166
Securities borrowed	3,331	2,957
Securities purchased under agreements to resell	1,242	2,035
Receivables from customer	27,017	29,821
Receivables from brokers, dealers and clearing organizations	706	823
Interest Receivable	141	116
Other assets	6	6
Total financial assets, not measured at fair value	43,825	44,924
Short-term borrowings	17	15
Securities loaned	4,037	4,444
Securities sold under agreements to repurchase		1,316
Customers	47,993	47,548
Brokers, dealers and clearing organizations	298	283
Interest Payable	41	22
Total financial liabilities, not measured at fair value	52,386	53,628
Level 3
Cash and cash equivalents
Cash - segregated for regulatory purposes
Securities - segregated for regulatory purposes
Securities borrowed
Securities purchased under agreements to resell
Receivables from customer
Receivables from brokers, dealers and clearing organizations
Interest Receivable
Other assets
Total financial assets, not measured at fair value
Short-term borrowings
Securities loaned
Securities sold under agreements to repurchase
Customers
Brokers, dealers and clearing organizations
Interest Payable
Total financial liabilities, not measured at fair value

Margin loans to clients stated net of allowance for doubtful accounts.

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