Insurance Premiums (Undiscounted Future Amount Of Premiums Expected To Be Collected And Period Which Those Collections Are Expected To Occur) (Detail) $ in Millions	Dec. 31, 2015 USD ($)
Insurance Premiums [Abstract]
Three months ending, March 31, 2016, Expected Collection of Premiums	$ 17
Three months ending, June 30, 2016, Expected Collection of Premiums	28
Three months ending, September 30, 2016, Expected Collection of Premiums	18
Three months ending, December 31, 2016, Expected Collection of Premiums	21
Twelve months ending, December 31, 2017, Expected Collection of Premiums	75
Twelve months ending, December 31, 2018, Expected Collection of Premiums	68
Twelve months ending, December 31, 2019, Expected Collection of Premiums	64
Twelve months ending, December 31, 2020, Expected Collection of Premiums	61
Five years ending, December 31, 2025, Expected Collection of Premiums	250
Five years ending, December 31, 2030, Expected Collection of Premiums	175
Five years ending, December 31, 2035 and thereafter, Expected Collection of Premiums	175
Total, Expected Collection of Premiums	$ 952