Employee and Agent Benefits (Details 5)	12 Months Ended
	Dec. 31, 2011
Qualified defined benefit pension plans | U.S. equity portfolios | Minimum
Asset category target allocation
Asset category target allocation	35%
Qualified defined benefit pension plans | U.S. equity portfolios | Maximum
Asset category target allocation
Asset category target allocation	60%
Qualified defined benefit pension plans | International equity portfolios | Minimum
Asset category target allocation
Asset category target allocation	5%
Qualified defined benefit pension plans | International equity portfolios | Maximum
Asset category target allocation
Asset category target allocation	20%
Qualified defined benefit pension plans | Fixed income security portfolios | Minimum
Asset category target allocation
Asset category target allocation	20%
Qualified defined benefit pension plans | Fixed income security portfolios | Maximum
Asset category target allocation
Asset category target allocation	40%
Qualified defined benefit pension plans | Real estate investment portfolios | Minimum
Asset category target allocation
Asset category target allocation	3%
Qualified defined benefit pension plans | Real estate investment portfolios | Maximum
Asset category target allocation
Asset category target allocation	10%
Other postretirement benefits | U.S. equity portfolios | Minimum
Asset category target allocation
Asset category target allocation	45%
Other postretirement benefits | U.S. equity portfolios | Maximum
Asset category target allocation
Asset category target allocation	65%
Other postretirement benefits | International equity portfolios | Minimum
Asset category target allocation
Asset category target allocation	5%
Other postretirement benefits | International equity portfolios | Maximum
Asset category target allocation
Asset category target allocation	15%
Other postretirement benefits | Fixed income security portfolios | Minimum
Asset category target allocation
Asset category target allocation	30%
Other postretirement benefits | Fixed income security portfolios | Maximum
Asset category target allocation
Asset category target allocation	50%