Consolidated Condensed Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Allowance for uncollectibles	$ 4.1	$ 4.2
Common equity, shares authorized	400.0	400.0
Common equity, par value	$ 1	$ 1
Common equity, shares outstanding	217.3	216.6
Tampa Electric Company [Member]
Allowance for uncollectibles	$ 1.4	$ 1.5