XML 94 R65.htm IDEA: XBRL DOCUMENT v3.8.0.1
Invested Assets and Investment Income - Summary of Invested Assets and Segregated Funds Net Assets, Measured at Fair Value (Parenthetical) (Detail)
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Bottom of range [Member]    
Disclosure of fair value measurement of assets [Line Items]    
Investment properties capitalization rates 3.50% 3.75%
Investment properties terminal capitalization rates 4.00% 4.10%
Top of range [Member]    
Disclosure of fair value measurement of assets [Line Items]    
Investment properties capitalization rates 9.00% 9.75%
Investment properties terminal capitalization rates 9.25% 10.00%
Power and infrastructure [Member] | Bottom of range [Member]    
Disclosure of fair value measurement of assets [Line Items]    
Other invested assets fair value discount rate 9.20% 9.63%
Power and infrastructure [Member] | Top of range [Member]    
Disclosure of fair value measurement of assets [Line Items]    
Other invested assets fair value discount rate 16.50% 16.00%
Timberland Investment [Member] | Bottom of range [Member]    
Disclosure of fair value measurement of assets [Line Items]    
Other invested assets fair value discount rate 5.00% 5.00%
Timberland Investment [Member] | Top of range [Member]    
Disclosure of fair value measurement of assets [Line Items]    
Other invested assets fair value discount rate 7.50% 7.50%