Employee Benefits Components of net periodic benefit cost (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
U.K. [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1	$ 1	$ 4
Interest cost	210	217	216
Expected return on plan assets	(302)	(274)	(238)
Amortization of prior-service cost	1	1	1
Amortization of net actuarial loss	49	43	39
Net periodic benefit cost	(41)	(12)	22
U.S. [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	7	0	0
Interest cost	114	119	122
Expected return on plan assets	(139)	(127)	(120)
Amortization of prior-service cost	0	0	0
Amortization of net actuarial loss	52	43	31
Net periodic benefit cost	34	35	33
Other [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	18	14	15
Interest cost	45	48	51
Expected return on plan assets	(59)	(49)	(49)
Amortization of prior-service cost	0	0	0
Amortization of net actuarial loss	23	17	14
Net periodic benefit cost	$ 27	$ 30	$ 31