Shareholders' Equity And Dividend Restrictions (Change In AOCI Includes Changes In Unrealized Gains And Losses On Investments And Pension Obligations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated other comprehensive income before tax
Accumulated unrealized gains on investments available for sale and other at beginning of period	$ 1,460	$ 1,232	$ 1,012
Increase in unrealized gains	428	309	383
Reclassification adjustment for (gains) losses included in net income	42	70	159
Adjustment to deferred acquisition costs and life policy reserves and other	(21)	(11)	(4)
Effect on other comprehensive income	365	228	220
Accumulated unrealized gains on investments available for sale and other at end of period	1,825	1,460	1,232
Accumulated unrealized losses for pension obligations at beginning of period	(88)	(63)	(66)
Change in pension obligations	(13)	(25)	3
Accumulated unrealized losses for pension obligations at end of period	(101)	(88)	(63)
Accumulated other comprehensive income at beginning of period	1,372	1,169	946
Unrealized investment gains and losses and other adjustments	365	228	220
Accumulated other comprehensive income at end of period	1,724	1,372	1,169
Accumulated other comprehensive income, tax
Accumulated unrealized gains on investments available for sale and other at beginning of period	502	422	345
Increase in unrealized gains	152	108	136
Reclassification adjustment for (gains) losses included in net income	(15)	(25)	(56)
Adjustment to deferred acquisition costs and life policy reserves and other	(9)	(3)	(3)
Effect on other comprehensive income	128	80	77
Accumulated unrealized gains on investments available for sale and other at end of period	630	502	422
Accumulated unrealized losses for pension obligations at beginning of period	(31)	(22)	(23)
Change in pension obligations	(4)	(9)	1
Accumulated unrealized losses for pension obligations at end of period	(35)	(31)	(22)
Accumulated other comprehensive income at beginning of period	471	400	322
Unrealized investment gains and losses and other adjustments	128	80	77
Accumulated other comprehensive income at end of period	595	471	400
Accumulated other comprehensive income net of tax
Accumulated unrealized gains on investments available for sale and other at beginning of period	958	810	667
Increase in unrealized gains	276	201	247
Reclassification adjustment for (gains) losses included in net income	(27)	(45)	(103)
Adjustment to deferred acquisition costs and life policy reserves and other	(12)	(8)	(1)
Effect on other comprehensive income	237	148	143
Accumulated unrealized gains on investments available for sale and other at end of period	1,195	958	810
Accumulated unrealized losses for pension obligations at beginning of period	(57)	(41)	(43)
Change in pension obligations	(9)	(16)	2
Accumulated unrealized losses for pension obligations at end of period	(66)	(57)	(41)
Accumulated other comprehensive income at beginning of period	901	769	624
Unrealized investment gains and losses and other adjustments	237	148	143
Accumulated other comprehensive income at end of period	$ 1,129	$ 901	$ 769