Acquisition/Divestitures	12 Months Ended
Dec. 31, 2011
Acquisition/Divestitures [Abstract]
Acquisition/Divestitures	Note 2. Acquisition/Divestitures In November of 2011, CNA completed the sale of its 50% ownership interest in First Insurance Company of Hawaii ("FICOH") and received $165 million in net proceeds. This sale did not have a significant impact on the Company's results of operations. On June 10, 2011, CNA completed the acquisition of all of the publicly traded shares of common stock of CNA Surety Corporation ("CNA Surety"). Prior to the acquisition, CNA owned approximately 61% of the outstanding common stock of CNA Surety. CNA Surety is now a wholly owned subsidiary of CNA. The aggregate purchase price was approximately $475 million. The amount paid to acquire the common shares of CNA Surety in excess of the closing date noncontrolling interests included in the Company's equity of $438 million was reflected as an adjustment to Additional paid-in capital of $54 million. In addition, Accumulated other comprehensive income increased by $17 million related to the portion of net unrealized gains previously allocated to the noncontrolling shareholders. Net income attributable to the noncontrolling interests for the years ended December 31, 2011, 2010 and 2009 was not significant. In December of 2011, Boardwalk HP Storage Company, LLC ("HP Storage") acquired seven salt dome natural gas storage caverns and associated assets in Mississippi for approximately $550 million. HP Storage funded the acquisition with proceeds from a $200 million five year variable rate term loan and equity contributions from Boardwalk Pipelines Holding Corp. ("BPHC") and Boardwalk Pipeline. BPHC, a wholly owned subsidiary of the Company, contributed $280 million for an 80% interest in HP Storage and Boardwalk Pipeline contributed $70 million for a 20% interest. HP Storage consolidated results are included in the Boardwalk Pipeline segment. In the fourth quarter of 2011, HighMount acquired working interests in oil and gas properties located in Oklahoma. The oil and gas properties acquired are primarily undeveloped and HighMount believes that they contain oil and liquid reserves which can be produced through horizontal drilling. The purchase price was approximately $106 million in cash and is included primarily in the cost of unproved properties within Property, plant and equipment in the Consolidated Balance Sheets. In the second quarter of 2010, HighMount completed the sale of substantially all exploration and production assets located in the Antrim Shale in Michigan and the Black Warrior Basin in Alabama for approximately $530 million. The Michigan and Alabama properties represented approximately 17% in aggregate of HighMount's total proved reserves as of December 31, 2009. These sales did not have a material impact on the Consolidated Statements of Income. In accordance with the full cost method of accounting, proceeds from these sales were accounted for as reductions of capitalized costs.

Note 2. Acquisition/Divestitures

In November of 2011, CNA completed the sale of its 50% ownership interest in First Insurance Company of Hawaii ("FICOH") and received $165 million in net proceeds. This sale did not have a significant impact on the Company's results of operations.

On June 10, 2011, CNA completed the acquisition of all of the publicly traded shares of common stock of CNA Surety Corporation ("CNA Surety"). Prior to the acquisition, CNA owned approximately 61% of the outstanding common stock of CNA Surety. CNA Surety is now a wholly owned subsidiary of CNA. The aggregate purchase price was approximately $475 million. The amount paid to acquire the common shares of CNA Surety in excess of the closing date noncontrolling interests included in the Company's equity of $438 million was reflected as an adjustment to Additional paid-in capital of $54 million. In addition, Accumulated other comprehensive income increased by $17 million related to the portion of net unrealized gains previously allocated to the noncontrolling shareholders. Net income attributable to the noncontrolling interests for the years ended December 31, 2011, 2010 and 2009 was not significant.

In December of 2011, Boardwalk HP Storage Company, LLC ("HP Storage") acquired seven salt dome natural gas storage caverns and associated assets in Mississippi for approximately $550 million. HP Storage funded the acquisition with proceeds from a $200 million five year variable rate term loan and equity contributions from Boardwalk Pipelines Holding Corp. ("BPHC") and Boardwalk Pipeline. BPHC, a wholly owned subsidiary of the Company, contributed $280 million for an 80% interest in HP Storage and Boardwalk Pipeline contributed $70 million for a 20% interest. HP Storage consolidated results are included in the Boardwalk Pipeline segment.

In the fourth quarter of 2011, HighMount acquired working interests in oil and gas properties located in Oklahoma. The oil and gas properties acquired are primarily undeveloped and HighMount believes that they contain oil and liquid reserves which can be produced through horizontal drilling. The purchase price was approximately $106 million in cash and is included primarily in the cost of unproved properties within Property, plant and equipment in the Consolidated Balance Sheets.

In the second quarter of 2010, HighMount completed the sale of substantially all exploration and production assets located in the Antrim Shale in Michigan and the Black Warrior Basin in Alabama for approximately $530 million. The Michigan and Alabama properties represented approximately 17% in aggregate of HighMount's total proved reserves as of December 31, 2009. These sales did not have a material impact on the Consolidated Statements of Income. In accordance with the full cost method of accounting, proceeds from these sales were accounted for as reductions of capitalized costs.