Summary Of Significant Accounting Policies (Details) - USD ($)			12 Months Ended
	Oct. 31, 2019	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Loan impairment threshold period			90 days
Threshold of reporting unit goodwill carrying value for further analysis			$ 0
Goodwill impairment charges	$ 0
Incremental payments due upon termination of contract			0
Right-of-use assets			725,800,000
Lease liabilities			707,039,000
Other operating expenses			325,444,000	$ 315,152,000	$ 297,634,000
ASU 2017-08 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative adjustments for accounting changes		$ 4,400,000
ASU 2016-02 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative adjustments for accounting changes		6,700,000
Right-of-use assets		$ 670,000,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]		us-gaap:PropertyPlantAndEquipmentNet
Lease liabilities		$ 670,000,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]		us-gaap:AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent
ASU 2018-02 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification adjustment related to cash flow hedges and investment portfolio credit risk			3,100,000
ASU 2016-18 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Increase in net cash provided by operating activities					$ 17,600,000
ASU 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative adjustments for accounting changes			4,200,000
Capital raising and advisory fee revenues			33,800,000
Other operating expenses			33,800,000
Minimum [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reserve for credit losses			107,500,000
Maximum [Member] | ASU 2016-13 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reserve for credit losses			$ 120,500,000
Office Equipment [Member] | Minimum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Fixed assets, Useful life			2 years
Office Equipment [Member] | Maximum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Fixed assets, Useful life			7 years
Building and Building Improvements [Member] | Minimum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Fixed assets, Useful life			3 years
Building and Building Improvements [Member] | Maximum [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Fixed assets, Useful life			39 years
Aircraft Engines Held for Operating Lease [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Fixed assets, Useful life			30 years
Fixed assets, residual value percentage			15.00%