Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Domestic Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 6	$ 17	$ 19
Interest cost	23	24	66	72
Expected return on plan assets	(31)	(30)	(90)	(89)
Net amortization	15	10	44	29
Net periodic benefit cost	12	10	37	31
Domestic Other Postretirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	3	10	8
Interest cost	8	9	25	27
Expected return on plan assets	(10)	(11)	(32)	(32)
Net amortization	1	1	4	1
Net periodic benefit cost	3	2	7	4
UK Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	5	16	15
Interest cost	21	21	63	64
Expected return on plan assets	(25)	(26)	(75)	(79)
Net amortization	14	11	41	33
Net periodic benefit cost	$ 15	$ 11	$ 45	$ 33