Shareholders' Equity - Comparison of GAAP and Statutory Net Income (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Comparison of GAAP and statutory net income (loss)
GAAP net income (loss)	$ 569	$ 541	$ 579	$ 656	$ 102	$ 533	$ 404	$ 506	$ 2,345	$ 1,545	$ 1,678
P&C Group [Member]
Comparison of GAAP and statutory net income (loss)
GAAP net income (loss)									2,480	1,791	1,915
Statutory net income									2,485	1,936	1,824
Corporate and Other [Member]
Comparison of GAAP and statutory net income (loss)
GAAP net income (loss)									$ (135)	$ (246)	$ (237)