Pension Plans, Retirement Benefits and Savings Plans (details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Plans [Member]
Defined benefit plan disclosure
Service cost	$ 27	$ 30	$ 82	$ 89
Interest cost on benefit obligation	38	33	113	99
Expected return on plan assets	(55)	(52)	(164)	(156)
Amortization of unrecognized net actuarial (gain) loss	17	27	49	80
Net periodic benefit cost	27	38	80	112
Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Interest cost on benefit obligation	3	3	8	7
Net periodic benefit cost, amortization of unrecognized prior service benefit	(1)	(1)	(2)	(2)
Amortization of unrecognized net actuarial (gain) loss	(1)		(2)
Net periodic benefit cost	$ 1	$ 2	$ 4	$ 5