Employee Benefit Plans, Amounts Recognized in Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net gain (loss) arising during the year:
Net actuarial gain (loss) arising during the year	$ 367	$ (228)	$ (285)
Prior service cost arising during the year		(9)	(4)
Remeasurement due to plan amendments	371
Net (gain) loss reclassified into income:
Net actuarial loss	57	34	14
Prior service cost (credit)	(33)	(20)	(21)
Curtailment and settlement loss	1	12	4
Total changes in other comprehensive income (loss)	763	(211)	(292)
Pension Plans [Member]
Net gain (loss) arising during the year:
Net actuarial gain (loss) arising during the year	290	(245)	(294)
Prior service cost arising during the year	0	(9)	(4)
Remeasurement due to plan amendments	328	0	0
Net (gain) loss reclassified into income:
Net actuarial loss	57	33	12
Prior service cost (credit)	(19)	3	2
Curtailment and settlement loss	1	12	4
Total changes in other comprehensive income (loss)	657	(206)	(280)
Other Postretirement Benefit Plans [Member]
Net gain (loss) arising during the year:
Net actuarial gain (loss) arising during the year	77	17	9
Prior service cost arising during the year	0	0	0
Remeasurement due to plan amendments	43	0	0
Net (gain) loss reclassified into income:
Net actuarial loss	0	1	2
Prior service cost (credit)	(14)	(23)	(23)
Curtailment and settlement loss	0	0	0
Total changes in other comprehensive income (loss)	$ 106	$ (5)	$ (12)