v3.25.2
Shareholders' equity - Issued and Outstanding Preferred Stock (Detail) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended 6 Months Ended 7 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Jul. 31, 2024
Dec. 31, 2024
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 10,215,000   10,215,000     10,215,000
Preferred stock, shares outstanding (in shares) 10,215,000   10,215,000     10,215,000
Carrying Amount $ 2,394   $ 2,394     $ 2,394
Preferred Series E            
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 0   0     0
Preferred stock, shares outstanding (in shares) 0   0     0
Preferred stock, liquidation preference per share (in USD per share) $ 1,000   $ 1,000      
Preferred stock dividend rate (as a percent)     0.00%      
Carrying Amount $ 0   $ 0     $ 0
Preferred stock per share dividend amount (in USD per share) $ 0 $ 22.95 $ 0 $ 39.075    
Preferred Series F            
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 50,000   50,000     50,000
Preferred stock, shares outstanding (in shares) 50,000   50,000     50,000
Preferred stock, liquidation preference per share (in USD per share) $ 10,000   $ 10,000      
Preferred stock dividend rate (as a percent)     5.125%      
Carrying Amount $ 500   $ 500     $ 500
Preferred stock per share dividend amount (in USD per share) $ 128.125 128.125 $ 256.25 256.25    
Preferred stock. dividend rate spread (as a percent)     3.78%      
Preferred Series G            
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 40,000   40,000     40,000
Preferred stock, shares outstanding (in shares) 40,000   40,000     40,000
Preferred stock, liquidation preference per share (in USD per share) $ 10,000   $ 10,000      
Preferred stock dividend rate (as a percent)     7.304%   5.00%  
Carrying Amount $ 400   $ 400     $ 400
Preferred stock per share dividend amount (in USD per share) $ 182.60 125.00 $ 365.20 250.00    
Preferred stock. dividend rate spread (as a percent)     3.174%      
Preferred Series H            
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 10,000,000   10,000,000     10,000,000
Preferred stock, shares outstanding (in shares) 10,000,000   10,000,000     10,000,000
Preferred stock, liquidation preference per share (in USD per share) $ 25   $ 25      
Preferred stock dividend rate (as a percent)     5.625%      
Carrying Amount $ 261   $ 261     $ 261
Preferred stock per share dividend amount (in USD per share) $ 0.3516 0.3516 $ 0.7031 0.7031    
Preferred stock. dividend rate spread (as a percent)     4.28%      
Preferred Series I            
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 50,000   50,000     50,000
Preferred stock, shares outstanding (in shares) 50,000   50,000     50,000
Preferred stock, liquidation preference per share (in USD per share) $ 10,000   $ 10,000      
Preferred stock dividend rate (as a percent)     3.50%      
Carrying Amount $ 500   $ 500     $ 500
Preferred stock per share dividend amount (in USD per share) $ 87.50 87.50 $ 175.00 175.00    
Preferred stock. dividend rate spread (as a percent)     2.679%      
Preferred Series J            
Class of Stock [Line Items]            
Preferred stock, shares issued (in shares) 75,000   75,000     75,000
Preferred stock, shares outstanding (in shares) 75,000   75,000     75,000
Preferred stock, liquidation preference per share (in USD per share) $ 10,000   $ 10,000      
Preferred stock dividend rate (as a percent)     7.50%      
Carrying Amount $ 733   $ 733     $ 733
Preferred stock per share dividend amount (in USD per share) $ 187.50 $ 0 $ 375.00 $ 0