Employee Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended	3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended
	Jun. 30, 2014	Dec. 31, 2014 Forecast	Jun. 30, 2014 Pension Benefits	Jun. 30, 2013 Pension Benefits	Jun. 30, 2014 Pension Benefits	Jun. 30, 2013 Pension Benefits	Apr. 30, 2014 Pension Benefits	Dec. 31, 2013 Pension Benefits	Jun. 30, 2014 Other Benefits	Jun. 30, 2013 Other Benefits	Jun. 30, 2014 Other Benefits	Jun. 30, 2013 Other Benefits	Apr. 30, 2014 Other Benefits	Dec. 31, 2013 Other Benefits	Jun. 30, 2014 Superannuation, SERP and ESBP	Jun. 30, 2013 Superannuation, SERP and ESBP	Jun. 30, 2014 Superannuation, SERP and ESBP	Jun. 30, 2013 Superannuation, SERP and ESBP	Jun. 30, 2014 Health plan benefit
Pension Plan and Other Postretirement Benefits Plan
Discount rate in determining benefit obligations							4.50%	4.90%					4.20%	4.60%
Decreased in plan's benefit obligation					$ 150														$ 29
Increase in plan's benefit obligation					162														21
Increase in accumulated other comprehensive loss before income taxes	4
Increase in estimated future benefit payments from 2014 through 2023	93
Components of net periodic benefit cost:
Service cost			18	21	39	43			2	3	5	7					1
Interest cost			26	24	54	49			3	3	6	6			1	1	2	2
Expected return on plan assets			(47)	(42)	(95)	(83)			(4)	(4)	(9)	(8)
Amortization of prior service cost			(3)		(3)				(1)		(1)
Recognized net actuarial loss			14	27	28	54				2		3			1		1	1
Total net periodic benefit cost		39	8	30	23	63				4	1	8			2	1	4	3
Total net periodic benefit cost		$ 71