Shareholders' Equity - Summary of Dividend Rates of Perpetual Preferred Stock Issued and Outstanding (Detail)	9 Months Ended
	Sep. 30, 2022
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3 month LIBOR + 0.75%, with floor of 3.75%, payable quarterly
Series C Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3 month LIBOR + 0.75%, with floor of 4.00%, payable quarterly
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3 month LIBOR + 0.67%, with floor of 4.00%, payable quarterly
Series E Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3 month LIBOR + 0.7675%, with floor of 4.00%, payable quarterly
Series F Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3 month LIBOR + 0.77%, with floor of 4.00%, payable quarterly
Series J Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	5.50% to, but excluding, May 10, 2023; 3 month LIBOR + 3.64% thereafter, payable quarterly
Series K Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	6.375% to, but excluding, May 10, 2024; 3 month LIBOR + 3.55% thereafter, payable quarterly
Series O Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	5.30%, payable semi-annually, from issuance date to, but excluding,November 10, 2026; 3 month LIBOR + 3.834%, payable quarterly, thereafter
Series P Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	5.00%, payable semi-annually, from issuance date to, but excluding,November 10, 2022; 3 month LIBOR + 2.874%, payable quarterly, thereafter
Series Q Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	5.50%, payable semi-annually, from issuance date to, but excluding, August 10, 2024; 5 year treasury rate + 3.623%, payable semi-annually, thereafter
Series R Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	4.95%, payable semi-annually, from issuance date to, but excluding, February 10, 2025; 5 year treasury rate + 3.224%, payable semi-annually, thereafter
Series S Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	4.40%, payable semi-annually, from issuance date to, but excluding,February 10, 2025; 5 year treasury rate + 2.85%, payable semi-annually thereafter
Series T Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3.80%, payable semi-annually, from issuance date to, but excluding, May 10, 2026; 5 year treasury rate + 2.969%, payable semi-annually, thereafter
Series U Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	3.65%, payable semi-annually, from issuance date to, but excluding, August 10, 2026; 5 year treasury rate + 2.915%, payable semi-annually, thereafter
Series V Preferred Stock
Class of Stock [Line Items]
Preferred stock dividend rate	4.125%, payable semi-annually, from issuance date to, but excluding, November 10, 2026; 5 year treasury rate + 2.949%, payable semi-annually, thereafter