Reinsurance (Tables)

12 Months Ended

Dec. 31, 2011

Deferred Policy Acquisition Costs or Unpaid Losses and Loss Expenses or Reinsurance [Abstract]

Effect of reinsurance on premiums written and earned

	Years Ended December 31
	2011			2010			2009
	(in millions)
Direct premiums written	$	12,302		$	11,952		$	11,813
Reinsurance assumed		548			391			370
Reinsurance ceded		(1,092	)		(1,107	)		(1,106	)
Net premiums written	$	11,758		$	11,236		$	11,077
Direct premiums earned	$	12,247		$	11,949		$	12,058
Reinsurance assumed		505			363			435
Reinsurance ceded		(1,108	)		(1,097	)		(1,162	)
Net premiums earned	$	11,644		$	11,215		$	11,331