Fair Value Measurements (Details 3) (Equitable Gas and Homeworks, USD $) In Millions, unless otherwise specified	Dec. 17, 2013
Fair value measurements
Preliminary estimated fair value of assets	$ 141.4
Preliminary estimated fair value of other contractual assets	32.5
Level 2 | Income approach models
Fair value measurements
Preliminary estimated fair value of assets	141.4
Preliminary estimated fair value of other contractual assets	$ 32.5