Employee Benefit Plans (Details Textuals) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Aggregate reduction in other comprehensive income (loss) before income tax	$ 842	$ 760	$ (165)
Employee Benefit Plans (Textuals) [Abstract]
Percentage of benefits calculated with the traditional formula	90.00%
Amortization of net actuarial gains or losses threshold percentage	10.00%
Aggregate reduction in other comprehensive income (loss) net of income tax	546	494	(96)
Subsidies	0	3	8
Total revenue from annuity and life insurance contracts recognized	54	47	46
Total investment income (loss) from annuity and life insurance contracts	867	885	767
Defined Contribution Plan, Cost Recognized	96	95	86
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate reduction in other comprehensive income (loss) before income tax	543	394	(166)
Aggregate projected benefit obligations	9,480	8,327	7,043
Estimated net actuarial losses amortized into net periodic benefit cost over the next year	225
Estimated prior service cost amortized into net periodic benefit cost over the next year	6
Weighted average expected return on plan assets	6.25%
United States Pension Plans of US Entity, Defined Benefit [Member] | Qualified Plan Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Required contributions	0
Expected future discretionary contributions	233
United States Pension Plans of US Entity, Defined Benefit [Member] | Non-Qualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate projected benefit obligations	1,100	997
Expected future discretionary contributions	61
Foreign Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate reduction in other comprehensive income (loss) before income tax	17	34	(14)
Aggregate projected benefit obligations	823	773	676
Weighted average expected return on plan assets	2.94%
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate reduction in other comprehensive income (loss) before income tax	281	327	13
Aggregate projected benefit obligations	2,375	2,093	1,808
Expected future discretionary contributions	78
Estimated net actuarial losses amortized into net periodic benefit cost over the next year	73
Estimated prior service cost amortized into net periodic benefit cost over the next year	(75)
Weighted average expected return on plan assets	5.75%
Foreign Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Aggregate reduction in other comprehensive income (loss) before income tax	1	5	2
Aggregate projected benefit obligations	$ 43	$ 39	$ 37
Weighted average expected return on plan assets	5.75%