Stockholders' Equity (Narrative) (Details) - USD ($)		3 Months Ended
	Jan. 17, 2024	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Oct. 31, 2021
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		10,000,000		10,000,000
Stockholders' equity		$ 12,101,800,000	$ 11,587,800,000	$ 11,897,900,000	$ 11,259,500,000
Common stock dividends (in usd per share)		$ 0.75	$ 0.75
Stock repurchase program, number of shares authorized to be repurchased (in shares)						25,000,000
Stock repurchase, shares (in shares)		1,647,526	1,050,227
Stock repurchase, aggregate cost		$ 132,000,000	$ 100,900,000
Share-based payment arrangement, shares withheld for tax withholding obligation (in shares)		373,623	326,811
Average price paid per share for common stock repurchased (in usd per share)		$ 80.11	$ 96.04
Preferred Stock
Class of Stock [Line Items]
Stockholders' equity		$ 884,900,000	$ 884,900,000	$ 884,900,000	$ 884,900,000
Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		5,000		5,000
Preferred stock, without par value (in dollars per share)		$ 0
Preferred stock, liquidation preference		$ 100,000
Depository shares, liquidation preference per share (in dollars per share)		$ 1,000
Preferred stock, annual dividend rate		4.60%
Preferred stock, dividend payment rate, variable rate		3.202%
Common stock dividends (in usd per share)	$ 2,300
Series D Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Stockholders' equity		$ 493,500,000		$ 493,500,000
Series E Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		16,000		16,000
Percentage of ownership interest per each depository shares		0.10%
Preferred stock, without par value (in dollars per share)		$ 0
Preferred stock, liquidation preference		$ 25,000
Depository shares, liquidation preference per share (in dollars per share)		$ 25
Preferred stock, annual dividend rate		4.70%
Common stock dividends (in usd per share)	$ 293.75
Series E Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Stockholders' equity		$ 391,400,000		$ 391,400,000
Series D Preferred Stock, Depositary Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		500,000
Preferred stock, shares issued (in shares)		500,000
Percentage of ownership interest per each depository shares		1.00%
Series E Preferred Stock Depositary Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		16,000,000
Preferred stock, shares issued (in shares)		16,000,000