Summary Of Information About Securities Sold (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Proceeds from unsettled trades	$ 12.3
Proceeds from sales including discontinued operations		$ 326

Proceeds From Sale Of Available For Sale Securities Including Discontinued Operations

No definition available.

Name:	tmk_ProceedsFromSaleOfAvailableForSaleSecuritiesIncludingDiscontinuedOperations
Namespace Prefix:	tmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration