CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Change in unrealized holding gains on investments, tax expense (benefit)	$ 59	$ (16)	$ 112	$ 11
Reclassification adjustment for gross gains included in net income, tax expense	5	5	13	23
Unrealized gains transferred to noncontrolling interest on sale of life affiliate, tax expense	$ 0	$ 0	$ 0	$ 4