Retirement and Postretirement Benefit 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 Benefit
Net periodic benefit costs:
Service cost	$ 3	$ 3	$ 9	$ 10
Interest cost	6	6	18	19
Expected return on plan assets	(8)	(7)	(25)	(23)
Recognized actuarial loss	1	10	4	18
Net periodic benefit cost	2	12	6	24
Employer contributions	1	1	4	3
Postretirement Benefit
Net periodic benefit costs:
Service cost	7	8	19	22
Interest cost	10	11	34	32
Recognized actuarial loss	4	9	16	29
Net periodic benefit cost	$ 21	$ 28	$ 69	$ 83