Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	$ 74	$ 76	$ 147	$ 150
Interest Cost	148	141	291	281
Expected Return on Plan Assets	(176)	(148)	(346)	(296)
Amortization of Deferred Amounts	7	6	13	9
Recognized Net Actuarial Loss	54	53	106	106
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	2	0	2
Gross Benefit Cost (Credit)	107	130	211	252
Dividends on ESOP Preferred Stock	0	0	0	0
Net Periodic Benefit Cost (Credit)	107	130	211	252
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected Long-term Return on Assets					7.20%
Other Retiree Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service Cost	38	48	75	95
Interest Cost	64	66	128	130
Expected Return on Plan Assets	(97)	(96)	(193)	(191)
Amortization of Deferred Amounts	(5)	(5)	(10)	(10)
Recognized Net Actuarial Loss	30	50	59	100
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Curtailments	0	0	0	0
Gross Benefit Cost (Credit)	30	63	59	124
Dividends on ESOP Preferred Stock	(16)	(18)	(32)	(35)
Net Periodic Benefit Cost (Credit)	$ 14	$ 45	$ 27	$ 89
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected Long-term Return on Assets					8.30%