Consolidated Statments of Comprehensive Income and Changes in Shareholders' Equity (Unaudited) (USD $) In Millions	Total	Shareholder Comprehensive Income Loss And Shareholders Equity [Member]	Common Stock	Additional Paid In Capital	Accumulated Other Comprehensive Income	Retained Earnings	Treasury Stock	Noncontrolling Interest
Total Comprehensive Income and Total Equity, beginning of period at Mar. 31, 2010			$ 88	$ 2,522	$ (530)	$ 8,840	$ (5,119)	$ 14
Additional Paid In Capital, Effects of stock issuance for employee benefit plans				4
Net unrealized appreciation (depreciation), fixed maturities					119
Net unrealized appreciation (depreciation), equity securities					(1)
Net unrealized appreciation (depreciation) on securities	118				118
Net unrealized appreciation (depreciation), derivatives	16				16
Net translation of foreign currencies	(43)				(43)
Postretirement benefit liability adjustment	(100)				(100)
Other comprehensive income (loss)					(9)
Shareholders' net income	294					294
Retained Earnings, Effects of stock issuance for employee benefit plans						(5)
Repurchase of common stock							(123)
Other, primarily issuance of treasury stock for employee benefit plans							14
Net income attributable to noncontrolling interest	1							1
Total Comprehensive Income and Total Equity, end of period at Jun. 30, 2010		5,976	88	2,526	(539)	9,129	(5,228)	15
Total Comprehensive Income and Total Equity, beginning of period at Dec. 31, 2009			88	2,514	(618)	8,625	(5,192)	12
Additional Paid In Capital, Effects of stock issuance for employee benefit plans				12
Effects of acquisition of noncontrolling interest				0
Net unrealized appreciation (depreciation), fixed maturities					191
Net unrealized appreciation (depreciation), equity securities					(1)
Net unrealized appreciation (depreciation) on securities	190				190
Net unrealized appreciation (depreciation), derivatives	20				20
Net translation of foreign currencies	(39)				(39)
Postretirement benefit liability adjustment	(92)				(92)
Other comprehensive income (loss)					79
Shareholders' net income	577					577
Retained Earnings, Effects of stock issuance for employee benefit plans						(62)
Common dividends declared (per share: $0.04; $0.04)						(11)
Repurchase of common stock							(123)
Other, primarily issuance of treasury stock for employee benefit plans							87
Net income attributable to noncontrolling interest	2							2
Accumulated other comprehensive income attributable to noncontrolling interest								1
Acquisition of noncontrolling interest								0
Total Comprehensive Income and Total Equity, end of period at Jun. 30, 2010		5,976	88	2,526	(539)	9,129	(5,228)	15
Total Comprehensive Income and Total Equity, beginning of period at Dec. 31, 2010	6,663		88	2,534	(614)	9,879	(5,242)	18
Additional Paid In Capital, Effects of stock issuance for employee benefit plans				18
Effects of acquisition of noncontrolling interest				4
Net unrealized appreciation (depreciation), fixed maturities					81
Net unrealized appreciation (depreciation), equity securities					0
Net unrealized appreciation (depreciation) on securities	81				81
Net unrealized appreciation (depreciation), derivatives	(10)				(10)
Net translation of foreign currencies	98				98
Postretirement benefit liability adjustment	9				9
Other comprehensive income (loss)					178
Shareholders' net income	837					837
Retained Earnings, Effects of stock issuance for employee benefit plans						(47)
Common dividends declared (per share: $0.04; $0.04)						(11)
Repurchase of common stock							(225)
Other, primarily issuance of treasury stock for employee benefit plans							149
Net income attributable to noncontrolling interest	1							1
Accumulated other comprehensive income attributable to noncontrolling interest								0
Acquisition of noncontrolling interest								(19)
Total Comprehensive Income and Total Equity, end of period at Jun. 30, 2011	7,548	7,548	88	2,556	(436)	10,658	(5,318)	0
Total Comprehensive Income and Total Equity, beginning of period at Mar. 31, 2011			88	2,547	(569)	10,270	(5,312)	0
Additional Paid In Capital, Effects of stock issuance for employee benefit plans				9
Net unrealized appreciation (depreciation), fixed maturities					89
Net unrealized appreciation (depreciation), equity securities					(2)
Net unrealized appreciation (depreciation) on securities	87				87
Net unrealized appreciation (depreciation), derivatives	(5)				(5)
Net translation of foreign currencies	46				46
Postretirement benefit liability adjustment	5				5
Other comprehensive income (loss)					133
Shareholders' net income	408					408
Retained Earnings, Effects of stock issuance for employee benefit plans						(20)
Repurchase of common stock							(62)
Other, primarily issuance of treasury stock for employee benefit plans							56
Net income attributable to noncontrolling interest	0							0
Total Comprehensive Income and Total Equity, end of period at Jun. 30, 2011	$ 7,548	$ 7,548	$ 88	$ 2,556	$ (436)	$ 10,658	$ (5,318)	$ 0