Acquisitions and Divestitures - Additional Information (Detail) $ / shares in Units, $ in Millions			3 Months Ended								12 Months Ended
	Jun. 29, 2018 USD ($) $ / shares	May 22, 2017 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) Hotel Acquisition	Dec. 31, 2018 USD ($) Hotel Acquisition	Dec. 31, 2017 USD ($) Hotel
Business Acquisition [Line Items]
Purchase of Boardwalk Pipelines common units												$ (1,718)
Revenues			$ 3,876	$ 3,675	$ 3,623	$ 3,757	$ 3,287	$ 3,608	$ 3,590	$ 3,581	$ 14,931	14,066	$ 13,735
Estimated goodwill recognized			767				665				767	665	659
Additional Paid-in Capital [Member]
Business Acquisition [Line Items]
Purchase of Boardwalk Pipelines common units												658
Accumulated Other Comprehensive Income (Loss) [Member]
Business Acquisition [Line Items]
Purchase of Boardwalk Pipelines common units												(29)
Altium Packing [Member]
Business Acquisition [Line Items]
Debt financing proceeds											250
Corporate [Member]
Business Acquisition [Line Items]
Revenues											1,163	857	645
Corporate [Member] | Altium Packing [Member]
Business Acquisition [Line Items]
Revenues											76
Boardwalk Pipeline [Member]
Business Acquisition [Line Items]
Increase to deferred income tax liabilities											213
Boardwalk Pipeline [Member] | Additional Paid-in Capital [Member]
Business Acquisition [Line Items]
Purchase of Boardwalk Pipelines common units											658
Boardwalk Pipeline [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Business Acquisition [Line Items]
Purchase of Boardwalk Pipelines common units											(29)
Altium Acquisition Holdings, Inc. [Member]
Business Acquisition [Line Items]
Payments for acquisition		$ 1,200
Cash payments funding acquisition		$ 620
Altium Acquisition Holdings, Inc. [Member] | Altium Packing [Member]
Business Acquisition [Line Items]
Revenues											933	868	498
Plastic Packaging Manufacturers Business Acquisition [Member] | Altium Packing [Member]
Business Acquisition [Line Items]
Payments for acquisition											260	40
Estimated goodwill recognized			99				10				$ 99	$ 10
Number of businesses acquired | Acquisition											3	3
Plastic Packaging Manufacturers Business Acquisition [Member] | Altium Packing [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Estimated intangible assets recognized			$ 87				$ 15				$ 87	$ 15
Boardwalk Gp Lp [Member] | Boardwalk Pipeline [Member] | Subsidiaries [Member]
Business Acquisition [Line Items]
Payments for acquisition	$ 1,500
Purchase price, per unit | $ / shares	$ 12.06
Loews Hotels And Co [Member]
Business Acquisition [Line Items]
Proceeds from sale of hotels											$ 118	$ 40	$ 31
Number of hotel properties sold | Hotel											1	1	2