Stockholders' Equity (Narrative) (Details) - USD ($)		3 Months Ended				6 Months Ended
	Apr. 16, 2024	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 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		10,000,000
Stockholders' equity		$ 12,655,800,000	$ 12,101,800,000	$ 11,635,700,000	$ 11,587,800,000	$ 12,655,800,000	$ 11,635,700,000	$ 11,897,900,000	$ 11,259,500,000
Common stock dividends (in usd per share)		$ 0.75	$ 0.75	$ 0.75	$ 0.75
Stock repurchase program, number of shares authorized to be repurchased (in shares)										25,000,000
Stock repurchase, shares (in shares)		3,001,216		1,361,828		4,648,742	2,412,055
Stock repurchase, aggregate cost		$ 250,800,000	$ 132,000,000.0	$ 99,300,000	$ 100,900,000	$ 382,800,000	$ 200,200,000
Share-based payment arrangement, shares withheld for tax withholding obligation (in shares)		9,394		14,596		383,017	341,407
Average price paid per share for common stock repurchased (in usd per share)		$ 83.57		$ 72.91		$ 82.35	$ 82.98
Preferred Stock
Class of Stock [Line Items]
Stockholders' equity		$ 884,900,000	$ 884,900,000	$ 884,900,000	$ 884,900,000	$ 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		5,000
Preferred stock, without par value (in dollars per share)		$ 0				$ 0
Preferred stock, liquidation preference		$ 100,000				$ 100,000
Depository shares, liquidation preference per share (in dollars per share)		$ 1,000				$ 1,000
Preferred stock, annual dividend rate						4.60%
Preferred stock, dividend payment rate, variable rate						3.202%
Series D Preferred Stock | Preferred Stock
Class of Stock [Line Items]
Stockholders' equity		$ 493,500,000				$ 493,500,000		$ 493,500,000
Series E Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		16,000				16,000		16,000
Percentage of ownership interest per each depository shares		0.10%				0.10%
Preferred stock, without par value (in dollars per share)		$ 0				$ 0
Preferred stock, liquidation preference		$ 25,000				$ 25,000
Depository shares, liquidation preference per share (in dollars per share)		$ 25				$ 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		$ 391,400,000
Series D Preferred Stock, Depositary Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		500,000				500,000
Preferred stock, shares issued (in shares)		500,000				500,000
Percentage of ownership interest per each depository shares		1.00%				1.00%
Series E Preferred Stock Depositary Shares
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)		16,000,000				16,000,000
Preferred stock, shares issued (in shares)		16,000,000				16,000,000