Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Significant Accounting Policies [Line Items]
Level 3 Proportion to fixed maturities and equity securities	2.10%	0.40%
Purchase of private placement corporate bonds	$ 184,000,000
Insurance policy charges	23,310,000	24,950,000	26,629,000
Advertising costs charged to earnings and included in other operating expense	16,000,000	16,000,000	12,000,000
Capitalized advertising costs	1,040,000,000	1,000,000,000
Original cost of property and equipment	125,000,000	119,000,000
Accumulated depreciation	79,000,000	71,000,000
Depreciation expense	7,100,000	6,800,000	6,000,000
Carrying value of investment in low-income housing interests	285,000,000	293,000,000
Obligations under future commitments for low-income housing interests	67,000,000
Goodwill acquired	44,700
Pretax state administrative issue expense		6,900,000
After tax state administrative issue expense		4,500,000
Estimated pretax litigation settlement expenses		12,000,000
Estimated after tax litigation settlement expense		7,800,000
Other Assets
Significant Accounting Policies [Line Items]
Carrying value of investment in low-income housing interests	275,000,000	281,000,000
Other Invested Assets
Significant Accounting Policies [Line Items]
Carrying value of investment in low-income housing interests	$ 10,000,000	$ 12,000,000
Equipment | Minimum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	2 years
Equipment | Maximum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	10 years
Building and Building Improvements | Minimum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	5 years
Building and Building Improvements | Maximum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	40 years
Life Insurance
Significant Accounting Policies [Line Items]
Proportion of future policy reserves which are not universal life type	0.82
Liability for future policy benefits, interest rate assumptions, low end	2.50%
Liability for future policy benefits, interest rate assumptions, high end	7.00%
Liability for future policy benefits, interest rate assumptions	5.90%
Torchmark Corporation 2011 Incentive Plan | Minimum
Significant Accounting Policies [Line Items]
Option grants contractual term	7 years
Vesting period	3 years
Torchmark Corporation 2011 Incentive Plan | Maximum
Significant Accounting Policies [Line Items]
Option grants contractual term	10 years
Vesting period	5 years
Previous Plan
Significant Accounting Policies [Line Items]
Option grants contractual term	10 years
Vesting period	5 years