DEI [Abstract] DEI [Abstract] Entities [Table] Entities [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock [Member] Common Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 7.750% Series B Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 7.750% Series B Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 7.750% Series B Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 7.000% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 7.000% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 7.000% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 6.875% Series D Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 6.875% Series D Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1,000th interest in a share of 6.875% Series D Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1000th interest in a share of 6.500% Series E Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1000th interest in a share of 6.500% Series E Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depository shares each representing a 1/1000th interest in a share of 6.500% Series E Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Entity Information [Line Items] Entity Information [Line Items] Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company Title of 12(b) Security Title of 12(b) Security Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Pre-commencement Tender Offer Pre-commencement Tender Offer Soliciting Material Soliciting Material Written Communications Written Communications City Area Code City Area Code Local Phone Number Local Phone Number Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity File Number Entity File Number Document Type Document Type Document Period End Date Document Period End Date Entity Registrant Name Entity Registrant Name Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Amendment Flag Amendment Flag