Benefit Plans - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Eligible age for several postretirement benefit plans			55 years
Eligible age for Medicare benefits			65 years
Increase of 1% in each year would increase the Company's accumulated postretirement benefit obligation			$ 2
Decrease of 1% in each year would decrease the Company's accumulated postretirement benefit obligation			$ 2
Health care cost trend rate			0.00%
Settlement payment			$ 88		$ 253
Settlement charges recognized due to settlement	$ 84		86
Defined benefit plan obligation, curtailment				$ 55
Gain recognized due to curtailment		$ 86
Accumulated benefit obligation for all defined benefit pension plans			3,100	$ 3,200
Future capital calls from various third party limited partnership investments			$ 119
Percentage of limited partnerships comprising of the carrying value that employ hedge fund strategies			76.60%	76.60%
Amount contributed to the savings plans			$ 107	$ 115	125
Stock-based Compensation, vesting period			4 years
Stock-based Compensation, expiration period			10 years
Recognized compensation expense			$ 32	$ 14	$ 12
Time-based Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Terms of Award			Right to receive one share of the Company's common stock for each vested RSU
Forfeited during the year			16,079
Performance-based Restricted Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Terms of Award			Receive one share of the Company's common stock for each vested PSU
Restricted Stock Units (RSUs) and Performance Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Grants In Period			367,908
Weighted average grant date fair value			$ 39.74
Stock Appreciation Rights (SARs) [Member]
Defined Benefit Plan Disclosure [Line Items]
SARs outstanding			5,982,880
Weighted average grant date fair value			$ 40.90
2016 Loews Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Stock-based Compensation, number of shares authorized			6,000,000
Stock-based Compensation, maximum number of shares to be granted to each individual			500,000
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate			5.00%	5.00%	5.00%
Defined benefit plan obligation, discount rate		3.60%		4.00%
Maximum [Member] | 2016 Loews Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Stock-based Compensation, number of shares to be forfeited under prior plan			3,000,000
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate			4.00%	4.00%	4.00%
Defined benefit plan obligation, discount rate		3.10%		3.90%
Second Anniversary [Member] | Time-based Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Second Anniversary [Member] | Performance-based Restricted Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Third Anniversary [Member] | Time-based Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Third Anniversary [Member] | Performance-based Restricted Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets invested in equity securities and limited partnerships, Minimum			40.00%
Target allocation of plan assets invested in equity securities and limited partnerships, Maximum			60.00%
Percentage of hedge fund strategies			57.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement payment			$ 101	$ 12
Defined benefit plan obligation, discount rate	3.70%		3.90%	4.00%	3.70%
Expected contribution to plan(s), next fiscal year			$ 15
Fair value of plan assets	$ 2,713		2,423	$ 2,500	$ 2,713
Pension Benefits [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 15		10	$ 10	$ 15
Postretirement Healthcare and Life Insurance Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to plan(s), next fiscal year			$ 3
Multi-Strategy Approach [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of hedge fund strategies			38.00%
Distressed Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of hedge fund strategies			5.00%
Defined Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of limited partnerships comprising of the carrying value that employ hedge fund strategies			87.00%	87.00%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan obligation, discount rate	3.40%		3.70%	3.70%	3.40%
Fair value of plan assets	$ 87		$ 86	$ 86	$ 87
Other Postretirement Benefits [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			$ 0	$ 0