Business Combinations - Preliminary Allocation (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Mar. 20, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair value of liabilities assumed:
Bargain purchase gain		$ 141	$ 0	$ 2,142	$ 0
Signature Bridge Bank
Business Acquisition [Line Items]
Purchase Price consideration	$ 85
Fair value of assets acquired:
Cash & cash equivalents	25,043
Loans held for sale	232
Total loans held for investment	11,741
CDI and other intangible assets	464
Other assets	526
Total assets acquired	38,006
Fair value of liabilities assumed:
Deposits	33,568
Other liabilities	2,211
Total liabilities assumed	35,779
Fair value of net identifiable assets	2,227
Bargain purchase gain	2,142			$ 2,100
Signature Bridge Bank | Previously Reported
Business Acquisition [Line Items]
Purchase Price consideration	85
Fair value of assets acquired:
Cash & cash equivalents	25,043
Loans held for sale	232
Total loans held for investment	12,218
CDI and other intangible assets	464
Other assets	679
Total assets acquired	38,636
Fair value of liabilities assumed:
Deposits	33,568
Other liabilities	2,982
Total liabilities assumed	36,550
Fair value of net identifiable assets	2,086
Bargain purchase gain	2,001
Signature Bridge Bank | Restatement Adjustment
Fair value of assets acquired:
Total loans held for investment	(477)
CDI and other intangible assets
Other assets	(153)
Total assets acquired	(630)
Fair value of liabilities assumed:
Deposits	0
Other liabilities	(771)
Total liabilities assumed	(771)
Fair value of net identifiable assets	141
Bargain purchase gain	141
Signature Bridge Bank | Commercial and industrial
Fair value of assets acquired:
Total loans held for investment	9,888
Signature Bridge Bank | Commercial and industrial | Previously Reported
Fair value of assets acquired:
Total loans held for investment	10,102
Signature Bridge Bank | Commercial and industrial | Restatement Adjustment
Fair value of assets acquired:
Total loans held for investment	(214)
Signature Bridge Bank | Commercial real estate
Fair value of assets acquired:
Total loans held for investment	1,680
Signature Bridge Bank | Commercial real estate | Previously Reported
Fair value of assets acquired:
Total loans held for investment	1,942
Signature Bridge Bank | Commercial real estate | Restatement Adjustment
Fair value of assets acquired:
Total loans held for investment	(262)
Signature Bridge Bank | Consumer and other
Fair value of assets acquired:
Total loans held for investment	173
Signature Bridge Bank | Consumer and other | Previously Reported
Fair value of assets acquired:
Total loans held for investment	174
Signature Bridge Bank | Consumer and other | Restatement Adjustment
Fair value of assets acquired:
Total loans held for investment	$ (1)