Insurance Liabilities (Details 2)			12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2013 Principal Life Insurance Company item	Dec. 31, 2013 1998 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2012 1998 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 1998 1998 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2013 2001 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2012 2001 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2001 2001 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2013 2004 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2012 2004 Funding agreement program Principal Life Insurance Company USD ($)	Nov. 30, 2007 2004 Funding agreement program Principal Life Insurance Company USD ($)	Feb. 28, 2006 2004 Funding agreement program Principal Life Insurance Company USD ($)	Mar. 31, 2004 2004 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2013 2006 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2012 2006 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2006 2006 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2006 2006 Funding agreement program Principal Life Insurance Company EUR (€)	Dec. 31, 2013 2011 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2012 2011 Funding agreement program Principal Life Insurance Company USD ($)	Dec. 31, 2011 2011 Funding agreement program Principal Life Insurance Company USD ($)
Funding agreement disclosures
Number of separate funding agreement programs			5
Number of funding agreement programs not guaranteed by PFG			3
Maximum authorized amount of funding agreements to be issued						$ 4,000,000,000			$ 7,000,000,000					$ 4,000,000,000			$ 5,300,000,000	€ 4,000,000,000			$ 5,000,000,000
Funding agreements	7,642,900,000	9,077,100,000		370,900,000	1,189,500,000		637,600,000	1,598,500,000		975,000,000	1,875,600,000				1,278,700,000	1,251,100,000			2,630,500,000	1,352,300,000
Additional maximum authorized amount of funding agreements to be issued												5,000,000,000	5,000,000,000
Amount of funding agreement authorization used at time additional amount authorized												$ 9,000,000,000	$ 4,000,000,000