Property, Plant and Equipment - DD&A Expense and Capital Expenditures (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
DD&A	$ 861	$ 774	$ 758
Capital Expend.	2,813	1,755	1,106
CNA Financial [Member]
Property, Plant and Equipment [Line Items]
DD&A	69	72	71
Capital Expend.	72	90	98
Diamond Offshore [Member]
Property, Plant and Equipment [Line Items]
DD&A	457	389	394
Capital Expend.	2,050	987	721
Boardwalk Pipeline [Member]
Property, Plant and Equipment [Line Items]
DD&A	292	275	256
Capital Expend.	378	305	247
Loews Hotels [Member]
Property, Plant and Equipment [Line Items]
DD&A	37	32	30
Capital Expend.	289	369	30
Corporate and Other [Member]
Property, Plant and Equipment [Line Items]
DD&A	6	6	7
Capital Expend.	$ 24	$ 4	$ 10