4. Debt

Debt consists of the following:


(in millions)	March 31, 2015		December 31, 2014
Senior debentures maturing June 15, 2021	$	300.0	$	300.0
Senior debentures maturing March 1, 2020		102.4		164.6
Senior debentures maturing October 15, 2025		81.1		81.1
Subordinated debentures maturing March 30, 2053		175.0		175.0
Subordinated debentures maturing February 3, 2027		59.7		59.7
FHLBB borrowings (secured)		125.0		125.0
Total principal debt	$	843.2	$	905.4
Unamortized debt discount		(1.7)		(1.9)
Total	$	841.5	$	903.5

During the first quarter of 2015, the Company repurchased senior debentures maturing March 1, 2020, with a carrying value of $61.5 million at a cost of $78.2 million, resulting in a loss of $16.7 million, which is included in other operating expenses.

At March 31, 2015, the Company was in compliance with the covenants associated with all of its debt indentures and credit arrangements.