Regulatory Capital and Restrictions (Information On The Capital Ratios) (Detail) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Amount	$ 5,923,265		$ 5,923,265		$ 5,822,369
CET1 risk-based capital, Actual Ratio	0.1065		0.1065		0.1071
CET1 risk-based capital, Minimum Requirement Amount	$ 2,502,484		$ 2,502,484		$ 2,446,344
CET1 risk-based capital, Well Capitalized Amount	3,614,699		3,614,699		3,533,608
Total risk-based capital, Actual Amount	$ 7,368,290		$ 7,368,290		$ 7,203,029
Total risk-based capital, Actual Ratio	0.1325		0.1325		0.1325
Total risk-based capital, Capital Requirements, Minimum Amount	$ 4,448,860		$ 4,448,860		$ 4,349,056
Total risk-based capital, Capital Requirements, Minimum Ratio	0.080		0.080		0.080
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 5,561,075		$ 5,561,075		$ 5,436,320
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	0.100		0.100		0.100
Tier 1 capital, Actual Amount	$ 6,207,244		$ 6,207,244		$ 6,106,348
Tier 1 capital, Actual Ratio	0.1116		0.1116		0.1123
Tier 1 capital, Capital Requirements, Minimum Amount	$ 3,336,645		$ 3,336,645		$ 3,261,792
Tier 1 capital, Capital Requirements, Minimum Ratio	0.060		0.060		0.060
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 4,448,860		$ 4,448,860		$ 4,349,056
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	0.080		0.080		0.080
Tier 1 leverage capital ratio, Actual Amount	$ 6,207,244		$ 6,207,244		$ 6,106,348
Tier 1 leverage capital ratio, Actual Ratio	0.0836		0.0836		0.0895
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 2,969,294		$ 2,969,294		$ 2,730,212
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	0.040		0.040		0.040
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 3,711,617		$ 3,711,617		$ 3,412,765
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	0.050		0.050		0.050
Dividends paid	$ 100,000	$ 125,000	$ 250,000	$ 125,000
Subsidiaries
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
CET1 risk-based capital, Actual Amount	$ 6,780,817		$ 6,780,817		$ 6,661,504
CET1 risk-based capital, Actual Ratio	0.1221		0.1221		0.1228
CET1 risk-based capital, Minimum Requirement Amount	$ 2,498,477		$ 2,498,477		$ 2,442,058
CET1 risk-based capital, Well Capitalized Amount	3,608,911		3,608,911		3,527,417
Total risk-based capital, Actual Amount	$ 7,350,677		$ 7,350,677		$ 7,165,935
Total risk-based capital, Actual Ratio	0.1324		0.1324		0.1320
Total risk-based capital, Capital Requirements, Minimum Amount	$ 4,441,736		$ 4,441,736		$ 4,341,437
Total risk-based capital, Capital Requirements, Minimum Ratio	0.080		0.080		0.080
Total risk-based capital, Capital Requirements, Well Capitalized Amount	$ 5,552,170		$ 5,552,170		$ 5,426,796
Total risk-based capital, Capital Requirements, Well Capitalized Ratio	0.100		0.100		0.100
Tier 1 capital, Actual Amount	$ 6,780,817		$ 6,780,817		$ 6,661,504
Tier 1 capital, Actual Ratio	0.1221		0.1221		0.1228
Tier 1 capital, Capital Requirements, Minimum Amount	$ 3,331,302		$ 3,331,302		$ 3,256,078
Tier 1 capital, Capital Requirements, Minimum Ratio	0.060		0.060		0.060
Tier 1 capital, Capital Requirements, Well Capitalized Amount	$ 4,441,736		$ 4,441,736		$ 4,341,437
Tier 1 capital, Capital Requirements, Well Capitalized Ratio	0.080		0.080		0.080
Tier 1 leverage capital ratio, Actual Amount	$ 6,780,817		$ 6,780,817		$ 6,661,504
Tier 1 leverage capital ratio, Actual Ratio	0.0914		0.0914		0.0977
Tier 1 leverage capital ratio, Capital Requirements, Minimum Amount	$ 2,967,209		$ 2,967,209		$ 2,727,476
Tier 1 leverage capital ratio, Capital Requirements, Minimum Ratio	0.040		0.040		0.040
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Amount	$ 3,709,012		$ 3,709,012		$ 3,409,345
Tier 1 leverage capital ratio, Capital Requirements, Well Capitalized Ratio	0.050		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		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		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		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		0.065

Amount of total capital as defined by regulatory framework.

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Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework.

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

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