Annual report pursuant to Section 13 and 15(d)

Subsequent Events (Details)

v3.6.0.2
Subsequent Events (Details)
12 Months Ended
Jan. 25, 2017
$ / shares
Dec. 31, 2016
$ / shares
$ / MMBTU
Dec. 31, 2015
$ / shares
Dec. 31, 2014
$ / shares
Nov. 01, 2018
$ / MMBTU
Jan. 27, 2015
Subsequent Event [Line Items]            
Dividends declared per share (in dollars per share)   $ 3 $ 2.75 $ 2.57    
Common Stock [Member] | Subsequent Event [Member]            
Subsequent Event [Line Items]            
Dividends declared per share (in dollars per share) $ 0.750          
Series A Cumulative Redeemable Preferred Stock [Member] | Depositary Shares [Member] | Subsequent Event [Member]            
Subsequent Event [Line Items]            
Depositary stock, dividends declared per share (in dollars per share) $ 0.4609375          
Series A Cumulative Redeemable Preferred Stock [Member] | Preferred Stock [Member]            
Subsequent Event [Line Items]            
Coupon rate percentage   7.375%       7.375%
Laclede Gas [Member]            
Subsequent Event [Line Items]            
Tariff rate (in dollars per MMBtu) | $ / MMBTU   12.385        
Forecast [Member] | Laclede Gas [Member]            
Subsequent Event [Line Items]            
Tariff rate (in dollars per MMBtu) | $ / MMBTU         6.386