Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Pension Benefits [Member]	Sep. 30, 2013 Pension Benefits [Member]	Sep. 30, 2014 Pension Benefits [Member]	Sep. 30, 2013 Pension Benefits [Member]	Sep. 30, 2014 Other Postretirement Benefits [Member]	Sep. 30, 2013 Other Postretirement Benefits [Member]	Sep. 30, 2014 Other Postretirement Benefits [Member]	Sep. 30, 2013 Other Postretirement Benefits [Member]	Mar. 31, 2013 Retiree Health Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) to other postretirement obligation due to plan ammendments													$ (57)
Increase (decrease) to shareholders' equity resulting from plan ammendments													37
Components of net pension cost and other postretirement benefits cost tables detail [Abstract]
Service cost					0	1	1	2	0	1	0	1
Interest cost					52	45	155	136	3	3	9	9
Expected long-term return on plan assets					(65)	(68)	(197)	(204)	(1)	(1)	(1)	(1)
Amortization of net loss from past experience					14	19	43	56	0	0	0	0
Amortization of prior service cost					0	0	0	0	(1)	0	(2)	(3)
Settlement loss					0	0	6	0	0	0	0	0
Curtailment (gain) loss					0	0	0	0	0	0	0	(19)
Net pension cost					1	(3)	8	(10)	1	3	6	(13)
Increase (decrease) to postretirement benefits liability adjustment pre-tax			(50)
Increase (decrease) to postretirement benefits liability adjustement after-tax	(10)	(12)	(33)	(73)
Domestic pension plan contributions							$ 113