CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 394	$ 723	$ 423	$ 766	$ 712	$ 175	$ (624)	$ 524	$ 2,306	$ 787	$ 911
Changes in:
Unrealized net capital gains and losses									1,434	452	1,911
Unrealized foreign currency translation adjustments									14	(12)	23
Unrecognized pension and other postretirement benefit cost									(302)	(239)	94
Other comprehensive income, after-tax									1,146	201	2,028
Comprehensive income									$ 3,452	$ 988	$ 2,939