Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Pension Benefits [Member]	Jun. 30, 2013 Pension Benefits [Member]	Jun. 30, 2014 Pension Benefits [Member]	Jun. 30, 2013 Pension Benefits [Member]	Jun. 30, 2014 Other Postretirement Benefits [Member]	Jun. 30, 2013 Other Postretirement Benefits [Member]	Jun. 30, 2014 Other Postretirement Benefits [Member]	Jun. 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													$ (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					1	0	1	1		0	0	0
Interest cost					52	46	103	91	3	3	6	6
Expected long-term return on plan assets					(66)	(68)	(132)	(136)		0	0	0
Amortization of net loss from past experience					15	18	29	37		0	0	0
Amortization of prior service cost						0	0	0	0	(1)	(1)	(3)
Settlement loss						0	6	0		0	0	0
Curtailment (gain) loss						0	0	0		0	0	(19)
Net pension cost					2	(4)	7	(7)	3	2	5	(16)
Increase (decrease) to postretirement benefits liability adjustment pre-tax			(36)
Increase (decrease) to postretirement benefits liability adjustement after-tax	(11)	(21)	(23)	(61)
Domestic pension plan contributions							$ 113