Common Stock, $1.00 par value per share Common Stock [Member] Entity Tax Identification Number Entity Tax Identification Number Entity File Number Entity File Number Former Address Former Address [Member] Cover page. Cover [Abstract] Title of 12(b) Security Title of 12(b) Security Local Phone Number Local Phone Number New York Stock Exchange NEW YORK STOCK EXCHANGE, INC. [Member] Class of Stock [Domain] Class of Stock [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 Written Communications Written Communications Entity Listings [Line Items] Entity Listings [Line Items] Trading Symbol Trading Symbol Exchange [Domain] Exchange [Domain] Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] Entity Addresses, Address Type [Axis] Entity Addresses, Address Type [Axis] City Area Code City Area Code 4.250% Junior Subordinated Debentures Subordinated Debt [Member] Address Type [Domain] Address Type [Domain] Entity Listings [Table] Entity Listings [Table] Document Period End Date Document Period End Date NYSE Texas, Inc. NYSE TEXAS, INC. [Member] Amendment Flag Amendment Flag Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Entity Address, City or Town Entity Address, City or Town Security Exchange Name Security Exchange Name 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