Pension and Other Postretirement Benefits (Details - Pension Plan Assets) (Pension Benefits [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 3,665		$ 3,298		$ 3,163
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Target investment allocation percentage of equity securities	37.00%
Target investment allocation percentage of fixed income	30.00%
Target investment allocation percentage of securities partnerships	15.00%
Target investment allocation percentage of hedge funds	10.00%
Target investment allocation percentage of real estate	8.00%
Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,360		1,294
Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,207		1,174
Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,098		830		657
Company Subsidiaries [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	3,400
Buyer Of Retirement Benefits Business [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	300
Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	982		903
Fixed Maturities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Fixed Maturities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	947		891
Fixed Maturities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	35		12
Federal Government and Agency [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	4		5
Federal Government and Agency [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Federal Government and Agency [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	4		5
Federal Government and Agency [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Corporate fixed maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	443		339
Corporate fixed maturities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Corporate fixed maturities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	416		332
Corporate fixed maturities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	27		7
Other asset and mortgage-backed securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	13		10
Other asset and mortgage-backed securities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Other asset and mortgage-backed securities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	8		8
Other asset and mortgage-backed securities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	5		2
Fund Investments And Pooled Separate Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	522	[1]	549	[1]
Fund Investments And Pooled Separate Accounts [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	[1]	0	[1]
Fund Investments And Pooled Separate Accounts [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	519	[1]	546	[1]
Fund Investments And Pooled Separate Accounts [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	3	[1]	3	[1]
Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,523		1,446
Equity securities [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,360		1,294
Equity securities [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	153		138
Equity securities [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	10		14
Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,216		1,168
Domestic [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	1,202		1,153
Domestic [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	4		1
Domestic [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	10		14
International, including funds and pooled seperate accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	307	[1]	278	[1]
International, including funds and pooled seperate accounts [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	158	[1]	141	[1]
International, including funds and pooled seperate accounts [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	149	[1]	137	[1]
International, including funds and pooled seperate accounts [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	[1]	0	[1]
Real estate and mortgage loans, including pooled separate accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	351	[1]	303	[1]
Real estate and mortgage loans, including pooled separate accounts [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	[1]	0	[1]
Real estate and mortgage loans, including pooled separate accounts [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0	[1]	0	[1]
Real estate and mortgage loans, including pooled separate accounts [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	351	[1]	303	[1]
Securities Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	328		314
Securities Partnerships [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Securities Partnerships [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Securities Partnerships [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	328		314		347
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	327		148
Hedge Funds [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Hedge Funds [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Hedge Funds [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	327		148		0
Guaranteed Deposit Account Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	47		39
Guaranteed Deposit Account Contract [Member] | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Guaranteed Deposit Account Contract [Member] | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Guaranteed Deposit Account Contract [Member] | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	47		39		24
Cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	107		145
Cash equivalents | Fair Value Inputs Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	0		0
Cash equivalents | Fair Value Inputs Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	107		145
Cash equivalents | Fair Value Inputs Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at fair value	$ 0		$ 0

[1] A pooled separate account has several participating benefit plans and each owns a share of the total pool of investments.