Regulatory Capital and Restrictions (Information On The Capital Ratios) (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Amount	$ 5,509,106		$ 2,804,290
CET1 risk-based capital, Actual Ratio	0.1146		0.1172
CET1 risk-based capital, Minimum Requirement Amount	$ 2,163,855		$ 1,076,871
CET1 risk-based capital, Well Capitalized Amount	3,125,569		1,555,480
Total risk-based capital, Actual Amount	$ 6,927,124		$ 3,265,064
Total risk-based capital, Actual Ratio	0.1441		0.1364
Total risk-based capital, Capital Requirements, Minimum Amount	$ 3,846,854		$ 1,914,436
Total risk-based capital, Capital Requirements, Minimum Ratio	0.080		0.080
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 4,808,567		$ 2,393,046
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	0.100		0.100
Tier 1 capital, Actual Amount	$ 5,793,085		$ 2,949,327
Tier 1 capital, Actual Ratio	0.1205		0.1232
Tier 1 capital, Capital Requirements, Minimum Amount	$ 2,885,140		$ 1,435,827
Tier 1 capital, Capital Requirements, Minimum Ratio	0.060		0.060
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 3,846,854		$ 1,914,436
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	0.080		0.080
Tier 1 leverage capital ratio, Actual Amount	$ 5,793,085		$ 2,949,327
Tier 1 leverage capital ratio, Actual Ratio	0.1110		0.0847
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 2,087,830		$ 1,393,607
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	0.040		0.040
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 2,609,787		$ 1,742,008
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	0.050		0.050
Dividends paid	$ 0	$ 60,000
Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Amount	$ 6,376,845		$ 3,034,883
CET1 risk-based capital, Actual Ratio	0.1328		0.1269
CET1 risk-based capital, Minimum Requirement Amount	$ 2,160,507		$ 1,075,920
CET1 risk-based capital, Well Capitalized Amount	3,120,732		1,554,107
Total risk-based capital, Actual Amount	$ 6,917,038		$ 3,273,300
Total risk-based capital, Actual Ratio	0.1441		0.1369
Total risk-based capital, Capital Requirements, Minimum Amount	$ 3,840,901		$ 1,912,747
Total risk-based capital, Capital Requirements, Minimum Ratio	0.080		0.080
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 4,801,127		$ 2,390,934
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	0.100		0.100
Tier 1 capital, Actual Amount	$ 6,376,845		$ 3,034,883
Tier 1 capital, Actual Ratio	0.1328		0.1269
Tier 1 capital, Capital Requirements, Minimum Amount	$ 2,880,676		$ 1,434,560
Tier 1 capital, Capital Requirements, Minimum Ratio	0.060		0.060
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 3,840,901		$ 1,912,747
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	0.080		0.080
Tier 1 leverage capital ratio, Actual Amount	$ 6,376,845		$ 3,034,883
Tier 1 leverage capital ratio, Actual Ratio	0.1219		0.0872
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 2,092,902		$ 1,392,821
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	0.040		0.040
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 2,616,128		$ 1,741,026
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	0.050		0.050
Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Ratio	0.045		0.045
Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets \| Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Ratio	0.045		0.045
Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Ratio	0.065		0.065
Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets \| Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Ratio	0.065		0.065

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Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework.

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