Employee Retirement Benefits (Net Periodic Benefit Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 22	$ 37	$ 39
Interest cost	68	72	72
Expected return on plan assets	(85)	(73)	(69)
Curtailment gain	(5)	0	0
Amortization	16	30	12
Net periodic benefit cost	16	66	54
Other Postretirement Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	6	6	6
Interest cost	8	9	9
Expected return on plan assets	0	0	0
Curtailment gain	0	0	0
Amortization	(4)	(3)	(7)
Net periodic benefit cost	$ 10	$ 12	$ 8