Net Revenue (Details - Total Revenue) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 07, 2019
Revenue from Contract with Customer [Abstract]
Net interest income									$ 1,852,000,000	$ 1,846,000,000	$ 1,485,000,000
Gains (losses) on securities and other, net									(23,000,000)	53,000,000	28,000,000
Other revenue									48,000,000	45,000,000	43,000,000
Revenues	$ 679,000,000	$ 767,000,000	$ 685,000,000	$ 755,000,000	$ 735,000,000	$ 720,000,000	$ 710,000,000	$ 708,000,000	2,886,000,000	2,873,000,000	2,366,000,000
Options contract [Member]
Disaggregation of Revenue [Line Items]
Contract rate												$ 0.65
Active trader pricing [Member]
Disaggregation of Revenue [Line Items]
Contract rate												$ 0.50
Commissions [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									421,000,000	498,000,000	441,000,000
Fees and service charges [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax									$ 588,000,000	$ 431,000,000	$ 369,000,000