Document and Entity Information	3 Months Ended
	Mar. 31, 2012	May 04, 2012
Document and entity information
Entity Registrant Name	ING LIFE INSURANCE & ANNUITY CO
Entity Central Index Key	0000837010
Document Type	10-Q
Document Period End Date	Mar. 31, 2012
Amendment Flag	true
Amendment Description	Q1 2012 XBRL exhibits are not being modified, but are being filed as part of an amendment to registrant’s Q1 2012 Form 10-Q (“Q1 10-Q”). Registrant’s Q1 10-Q is being amended and restated in its entirety (the “Q1 10-Q/A”) for the sole purpose of filing Exhibit 18.1 (Letter of Independent Registered Public Accounting Firm concerning change in accounting principle) to the Q1 10-Q, which Exhibit was inadvertently omitted from the original Q1 10-Q filing. No other items of the original filing on Form 10-Q are modified by the Q1 10-Q/A.
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		55,000
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1