Acquisitions and Divestitures - Additional Information (Detail) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) Hotel	Dec. 31, 2014 USD ($) Property Hotel	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Number of remaining natural gas and oil properties | Property			0
Purchase price		$ 157	$ 448	$ 235
Goodwill recorded		351	374	357
Amount paid for acquisition		1,718	2,813	1,755
Evangeline Pipeline System [Member]
Business Acquisition [Line Items]
Purchase price	$ 295
Bluegrass Project [Member]
Business Acquisition [Line Items]
Previous period capitalized costs recorded as charge in present period in other operating expenses, net of tax and noncontrolling interest			55
Bluegrass Project [Member] | Other Operating Expenses [Member]
Business Acquisition [Line Items]
Previous period capitalized costs recorded as charge in present period in other operating expenses			94
Loews Hotels [Member]
Business Acquisition [Line Items]
Amount paid for acquisition		$ 330	$ 230
Number of hotel properties acquired | Hotel		2	3
CAC [Member]
Business Acquisition [Line Items]
Percentage of coinsurance agreement		100.00%
Recognized loss due to difference between market value and book value of funds withheld assets			$ 31
Boardwalk Pipeline [Member]
Business Acquisition [Line Items]
Goodwill recorded		$ 237	237	215
Amount paid for acquisition		390	378	$ 305
Boardwalk Pipeline [Member] | Evangeline Pipeline System [Member]
Business Acquisition [Line Items]
Identifiable finite-lived intangible assets		20
Goodwill recorded		$ 22
Boardwalk Pipeline Partners, LP [Member] | Bluegrass Project [Member]
Business Acquisition [Line Items]
Previous period capitalized costs recorded as charge in present period in other operating expenses			$ 10