Shareholders' Equity - Narrative (Details)											1 Months Ended				12 Months Ended
	Dec. 31, 2022 USD ($) period director $ / shares shares	Dec. 15, 2022 $ / shares	Sep. 30, 2022 $ / shares	Sep. 15, 2022 $ / shares	Jun. 30, 2022 $ / shares	Jun. 15, 2022 $ / shares	Mar. 31, 2022 $ / shares	Mar. 13, 2022 $ / shares	Jun. 05, 2020 USD ($) $ / shares shares	Jun. 27, 2013 USD ($) shares	Jul. 31, 2021 USD ($) $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	May 31, 2013 USD ($) $ / shares shares	Mar. 31, 2004 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) period director $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	Aug. 02, 2022 USD ($)	Aug. 11, 2021 USD ($)	Mar. 26, 2020 USD ($)
Class of Stock [Line Items]
Aggregate authorized shares (in shares) | shares	325,000,000														325,000,000
Authorized common shares (in shares) | shares	225,000,000														225,000,000
Authorized preference shares (in shares) | shares	100,000,000														100,000,000
Par value (in usd per share)	$ 1.00														$ 1.00	$ 1.00
Preference shares, issued, value | $															$ 0	$ 488,653,000	$ 0
Preference shares, shares outstanding (in shares) | shares	30,000														30,000	30,000
Dividends declared per common share (in usd per share)								$ 0.37
Dividends on preference shares | $															$ 35,375,000	$ 33,266,000	30,923,000
Dividends on common shares | $															$ 64,700,000	$ 67,800,000	$ 68,500,000
Common shares
Class of Stock [Line Items]
Proceeds from issuance of equity | $									$ 1,100,000,000
Dividends declared per common share (in usd per share)		$ 0.37		$ 0.37		$ 0.37
Dividends paid per common share (in usd per share)	$ 0.37		$ 0.37		$ 0.37		$ 0.37
Share repurchase program, authorized aggregate amount | $																		$ 500,000,000
Share repurchase program, shares repurchased (in shares) | shares															1,100,000
Repurchase of shares | $															$ 162,800,000
Share repurchase program, price per share (in usd per share)															$ 155.00
Share repurchase program, remaining authorized amount | $	$ 500,000,000														$ 500,000,000
Common shares | Underwritten Follow-On Offering
Class of Stock [Line Items]
Sale of stock, number of shares issued (in shares) | shares									6,325,000
Sale of stock, price per share (in usd per share)									$ 166.00
Common shares | Private Placement
Class of Stock [Line Items]
Sale of stock, number of shares issued (in shares) | shares									451,807
Proceeds from issuance of equity | $									$ 75,000,000
Series F Preferred Stock
Class of Stock [Line Items]
Sale of stock, number of shares issued (in shares) | shares												10,000
Proceeds from issuance of equity | $												$ 250,000,000
Dividend rate, percentage															5.75%
Par value (in usd per share)	$ 1.00														$ 1.00
Liquidation preference (in usd per share)												$ 25,000
Liquidation preference per annum (in usd per share)	1,437.5														1,437.5
Quarterly liquidation preference (in usd per share)	359.375														359.375
Series F Preferred Stock | Redemption period one
Class of Stock [Line Items]
Redemption price per share (in usd per share)	25,000														25,000
Depositary Shares, each representing a 1/1,000th interest in a Series F 5.750% Preference Share, Par Value $1.00 per share
Class of Stock [Line Items]
Sale of stock, number of shares issued (in shares) | shares												10,000,000
Depositary Shares
Class of Stock [Line Items]
Percentage interest in underlying shares											0.10%	0.10%
Depositary Shares | Redemption period one
Class of Stock [Line Items]
Redemption price per share (in usd per share)	25.00														$ 25.00
Series G Preferred Stock
Class of Stock [Line Items]
Sale of stock, number of shares issued (in shares) | shares											20,000
Proceeds from issuance of equity | $											$ 500,000,000
Dividend rate, percentage															4.20%
Liquidation preference (in usd per share)											$ 25,000
Liquidation preference per annum (in usd per share)	1,050														$ 1,050
Quarterly liquidation preference (in usd per share)	262.50														262.50
Series G Preferred Stock | Redemption period one
Class of Stock [Line Items]
Redemption price per share (in usd per share)	$ 25,000														$ 25,000
Depositary Shares, each representing a 1/1,000th interest in a Series G 4.20% Preference Share, Par Value $1.00 per share
Class of Stock [Line Items]
Sale of stock, number of shares issued (in shares) | shares											20,000,000
Series C Preferred Stock
Class of Stock [Line Items]
Dividend rate, percentage															6.08%
Par value (in usd per share)														$ 25
Preference shares, issued, value | $														$ 250,000,000
Preference shares, shares issued (in shares) | shares														10,000,000
Preference shares, shares redeemed (in shares) | shares										5,000,000
Preference shares, redemption amount | $										$ 125,000,000										$ 125,000,000
Preference shares, shares outstanding (in shares) | shares	0														0
Right to elect directors, required number of dividend periods in arrears | period	6														6
Right to elect directors, number of directors | director	2														2
Liquidation preference per annum (in usd per share)	$ 1.52														$ 1.52
Quarterly liquidation preference (in usd per share)	$ 0.38														$ 0.38
Series E Preferred Stock
Class of Stock [Line Items]
Dividend rate, percentage															5.375%
Par value (in usd per share)													$ 25
Preference shares, issued, value | $													$ 275,000,000
Preference shares, shares issued (in shares) | shares													11,000,000
Preference shares, redemption amount | $																			$ 275,000,000
Preference shares, shares outstanding (in shares) | shares	0														0
Liquidation preference per annum (in usd per share)	$ 1.34375														$ 1.34375
Quarterly liquidation preference (in usd per share)	0.3359375														0.3359375
Series F Preferred Shares, Depositary Shares
Class of Stock [Line Items]
Liquidation preference per annum (in usd per share)	1.4375														1.4375
Quarterly liquidation preference (in usd per share)	0.359375														0.359375
Series G Preferred Shares, Depositary Shares
Class of Stock [Line Items]
Liquidation preference per annum (in usd per share)	1.05														1.05
Quarterly liquidation preference (in usd per share)	$ 0.2625														$ 0.2625