Summary Of Fair Value Per Option Estimated On Date Of Grant (Detail)
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12 Months Ended | ||
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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WRL Stock Plan
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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
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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 |