Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets period End	$ 9,880		$ 9,150
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation Period Start	21,489	[1]	19,293
Defined Benefit Plan, Service Cost	0		0		0
Defined Benefit Plan, Interest Cost	861		930		969
Defined Benefit Plan, Actuarial Net (Gains) Losses	(2,212)		2,334
Defined Benefit Plan, Benefits Paid	(1,078)		(1,057)
Defined Benefit Plan, Contributions by Plan Participants	0		0
Defined Benefit Plan, Plan Amendments	0		0
Defined Benefit Plan, Special Termination Benefits	0		0
Defined Benefit Plan, Settlements, Benefit Obligation	0		(11)
Defined Benefit Plan, Benefit Obligation Period End	19,060	[1]	21,489	[1]	19,293
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets Period Start	8,196		7,789
Defined Benefit Plan, Actual Return on Plan Assets	905		778
Defined Benefit Plan, Contributions by Employer	914		697
Defined Benefit Plan, Contributions by Plan Participants	0		0
Defined Benefit Plan, Benefits Paid	(1,078)		(1,057)
Defined Benefit Plan, Settlements, Plan Assets	0		(11)
Defined Benefit Plan, Fair Value of Plan Assets period End	8,937		8,196		7,789
Defined Benefit Plan, Funded Status of Plan [Abstract]
Defined Benefit Plan, Funded Status of Plan	(10,123)		(13,293)
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined Benefit Plan, Benefit Obligation Period Start	3,582	[1]	3,570
Defined Benefit Plan, Service Cost	49		56		52
Defined Benefit Plan, Interest Cost	143		164		180
Defined Benefit Plan, Actuarial Net (Gains) Losses	(301)		147
Defined Benefit Plan, Benefits Paid	(313)		(310)
Defined Benefit Plan, Contributions by Plan Participants	45		58
Defined Benefit Plan, Plan Amendments	0		(219)
Defined Benefit Plan, Special Termination Benefits	0		116
Defined Benefit Plan, Settlements, Benefit Obligation	0		0
Defined Benefit Plan, Benefit Obligation Period End	3,205	[1]	3,582	[1]	3,570
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets Period Start	1,004		972
Defined Benefit Plan, Actual Return on Plan Assets	129		134
Defined Benefit Plan, Contributions by Employer	191		222
Defined Benefit Plan, Contributions by Plan Participants	45		58
Defined Benefit Plan, Benefits Paid	(313)		(310)
Defined Benefit Plan, Fair Value of Plan Assets, Period Increase (Decrease)	(326)		(382)
Defined Benefit Plan, Settlements, Plan Assets	0		0
Defined Benefit Plan, Fair Value of Plan Assets period End	1,043		1,004		972
Defined Benefit Plan, Funded Status of Plan [Abstract]
Defined Benefit Plan, Funded Status of Plan	$ (2,162)		$ (2,578)

[1] (1) At each period-end presented, our accumulated benefit obligations for our pension plans are equal to the benefit obligations shown above.