v3.26.1
Regulatory Requirements - Regulatory Capital and Ratios (Details)
$ in Millions
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
CSC    
Common Equity Tier 1 Risk-Based Capital    
Actual Amount $ 35,131 $ 36,081
Actual Ratio 0.263 0.304
Minimum Capital Requirement Amount $ 6,011 $ 5,345
Minimum Capital Requirement Ratio 0.045 0.045
Tier 1 Risk-Based Capital    
Actual Amount $ 41,894 $ 42,844
Actual Ratio 0.314 0.361
Minimum Capital Requirement Amount $ 8,014 $ 7,127
Minimum Capital Requirement Ratio 0.060 0.060
Total Risk-Based Capital    
Actual Amount $ 41,937 $ 42,894
Actual Ratio 0.314 0.361
Minimum Capital Requirement Amount $ 10,686 $ 9,503
Minimum Capital Requirement Ratio 0.080 0.080
Tier 1 Leverage    
Actual Amount $ 41,894 $ 42,844
Actual Ratio 0.089 0.093
Minimum Capital Requirement Amount $ 18,857 $ 18,499
Minimum Capital Requirement Ratio 0.040 0.040
Supplementary Leverage Ratio    
Actual Amount $ 41,894 $ 42,844
Actual Ratio 0.088 0.092
Minimum Capital Requirement Amount $ 14,268 $ 13,974
Minimum Capital Requirement Ratio 0.030 0.030
CSB    
Common Equity Tier 1 Risk-Based Capital    
Actual Amount $ 27,474 $ 28,126
Actual Ratio 0.340 0.359
Minimum to be Well Capitalized Amount $ 5,255 $ 5,088
Minimum to be Well Capitalized Ratio 0.065 0.065
Minimum Capital Requirement Amount $ 3,638 $ 3,523
Minimum Capital Requirement Ratio 0.045 0.045
Tier 1 Risk-Based Capital    
Actual Amount $ 27,474 $ 28,126
Actual Ratio 0.340 0.359
Minimum to be Well Capitalized Amount $ 6,467 $ 6,262
Minimum to be Well Capitalized Ratio 0.080 0.080
Minimum Capital Requirement Amount $ 4,850 $ 4,697
Minimum Capital Requirement Ratio 0.060 0.060
Total Risk-Based Capital    
Actual Amount $ 27,512 $ 28,163
Actual Ratio 0.340 0.360
Minimum to be Well Capitalized Amount $ 8,084 $ 7,828
Minimum to be Well Capitalized Ratio 0.100 0.100
Minimum Capital Requirement Amount $ 6,467 $ 6,262
Minimum Capital Requirement Ratio 0.080 0.080
Tier 1 Leverage    
Actual Amount $ 27,474 $ 28,126
Actual Ratio 0.109 0.111
Minimum to be Well Capitalized Amount $ 12,601 $ 12,641
Minimum to be Well Capitalized Ratio 0.050 0.050
Minimum Capital Requirement Amount $ 10,081 $ 10,113
Minimum Capital Requirement Ratio 0.040 0.040
Supplementary Leverage Ratio    
Actual Amount $ 27,474 $ 28,126
Actual Ratio 0.108 0.110
Minimum Capital Requirement Amount $ 7,635 $ 7,649
Minimum Capital Requirement Ratio 0.030 0.030