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Summary Of Fair Value Per Option Estimated On Date Of Grant (Detail)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
WRL Stock Plan
     
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]      
Expected dividend yield 4.00% 4.00% 1.23%
Expected stock price volatility 48.80% 49.70% 60.90%
Risk-free interest rate 1.18% 2.40% 3.10%
Expected average life of options (years) 7 years 6 years 6 months 6 years 10 months 24 days
WML Stock Plan
     
Share Based Payment Award Stock Options Valuation Assumptions [Line Items]      
Expected dividend yield 4.00% 4.00%  
Expected stock price volatility 49.00% 37.80% 40.80%
Risk-free interest rate 0.67% 2.10% 2.40%
Expected average life of options (years) 6 years 6 months 6 years 6 months 6 years 6 months