Entity Tax Identification Number Entity Tax Identification Number 7.35% Collateral Trust Bonds, due 2026 7.35% Collateral Trust Bonds, due 2026 [Member] 7.35% Collateral Trust Bonds, due 2026 Entity File Number Entity File Number Cover [Abstract] Title of 12(b) Security Title of 12(b) Security Local Phone Number Local Phone Number Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Soliciting Material Soliciting Material Entity Address, Address Line One Entity Address, Address Line One 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 5.50% Subordinated Notes, due 2064 5.50% Subordinated Notes, due 2064 [Member] 5.50% Subordinated Notes, due 2064 Written Communications Written Communications Trading Symbol Trading Symbol Debt Instrument [Axis] Debt Instrument [Axis] City Area Code City Area Code Document Information [Table] Document Information [Table] Document Period End Date Document Period End Date Amendment Flag Amendment Flag Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Entity Address, City or Town Entity Address, City or Town Document [Domain] Document [Domain] Security Exchange Name Security Exchange Name Document Information, Document [Axis] Document Information, Document [Axis] Document Information [Line Items] Document Information [Line Items] Document Type Document Type Pre-commencement Tender Offer Pre-commencement Tender Offer Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company