Common Stock [Member] Common 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] DEI [Abstract] DEI [Abstract] DEI [Abstract] Entity Tax Identification Number Entity Tax Identification Number Entity File Number Entity File Number Legal Entity [Axis] Legal Entity [Axis] Title of 12(b) Security Title of 12(b) Security Depositary shares each representing a 1/1000th interest in a share of 7.75% Series G Fixed Rate Reset Cumulative Redeemable Preferred Stock Depositary shares each representing a 1/1000th interest in a share of 7.75% Series G Fixed Rate Reset Cumulative Redeemable Preferred Stock [Member] Depositary shares each representing a 1/1000th interest in a share of 7.75% Series G Fixed Rate Reset Cumulative Redeemable Preferred Stock Entities [Table] Entities [Table] Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Entity Address, Address Line One Entity Address, Address Line One Soliciting Material Soliciting Material Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Entity Address, State or Province Entity Address, State or Province Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Written Communications Written Communications Entity Information [Line Items] Entity Information [Line Items] Trading Symbol Trading Symbol City Area Code City Area Code Depositary shares each representing a 1/1000th interest in a share of 6.125% Series F Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depositary shares each representing a 1/1000th interest in a share of 6.125% Series F Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Depositary shares each representing a 1/1000th interest in a share of 6.125% Series F Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock [Member] Document Period End Date Document Period End Date Amendment Flag Amendment Flag Entity Address, City or Town Entity Address, City or Town Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer 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] Entity [Domain] Entity [Domain] Current Fiscal Year End Date Current Fiscal Year End Date Security Exchange Name Security Exchange Name 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] Document Type Document Type Class of Stock [Axis] Class of Stock [Axis] Pre-commencement Tender Offer Pre-commencement Tender Offer Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company