Employee Benefits (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other changes in plan assets and benefit obligations recognized in other comprehensive income, net of tax
Total recognized	$ 215	$ (231)	$ 101
Retirement Plans [Member]
Components of net periodic cost for retirement plans and post-retirement plans
Service cost	5	10	24
Interest cost	99	91	93
Expected return on assets	(138)	(129)	(124)
Actuarial loss (gain)	11	26	32
Prior service cost (credit)	0	5	(1)
Curtailment	0	(8)	0
Net periodic benefit cost	(23)	(5)	24
Other changes in plan assets and benefit obligations recognized in other comprehensive income, net of tax
Net actuarial loss (gain)	232	(213)	116
Recognized actuarial (gain) loss	(7)	(15)	(20)
Prior service cost (credit)	0	5	2
Total recognized	225	(223)	98
Postretirement Plans [Member]
Components of net periodic cost for retirement plans and post-retirement plans
Service cost	1	2	3
Interest cost	4	5	5
Expected return on assets	0	0	0
Actuarial loss (gain)	(1)	0	0
Prior service cost (credit)	0	(1)	(1)
Curtailment	(1)	(12)	0
Net periodic benefit cost	3	(6)	7
Other changes in plan assets and benefit obligations recognized in other comprehensive income, net of tax
Net actuarial loss (gain)	3	(8)	2
Recognized actuarial (gain) loss	1	0	0
Prior service cost (credit)	(5)	0	1
Total recognized	$ (1)	$ (8)	$ 3