Employee Benefits Reconciliation of the changes in the benefit obligations and fair value of assets and a statement of the funded status (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
U.K. [Member]
Change in projected benefit obligation
Balance at the beginning of the Period	$ 4,944	$ 4,520
Service cost	1	1	4
Interest cost	210	217	216
Participant contributions	0	0
Plan amendment	0	0
Curtailments	0	0
Plan transfer and acquisitions	0	0
Actuarial loss (gain)	145	(116)
Benefit payments	(186)	(153)
Actual expenses	0	0
Change in discount rate	(95)	324
Foreign currency impact	87	151
Balance at the end of the period	5,106	4,944	4,520
Accumulated benefit obligation at end of year	5,106	4,944
Change in fair value of plan assets
Balance at the beginning of the period	4,860	4,245
Actual return on plan assets	304	281
Participant contributions	0	0
Employer contributions	316	341
Plan transfer and acquisitions	0	0
Benefit payments	(186)	(153)
Actual expenses	0	0
Foreign currency impact	104	146
Balance at the end of the period	5,398	4,860	4,245
Market related value at end of year	5,398	4,860
Funded status	292	(84)
Unrecognized prior-service cost	24	24
Unrecognized loss	2,012	1,981
Net amount recognized	2,328	1,921
U.S. [Member]
Change in projected benefit obligation
Balance at the beginning of the Period	2,884	2,657
Service cost	7	0	0
Interest cost	114	119	122
Participant contributions	0	0
Plan amendment	12	0
Curtailments	0	0
Plan transfer and acquisitions	115	0
Actuarial loss (gain)	17	29
Benefit payments	(128)	(123)
Actual expenses	0	0
Change in discount rate	(277)	202
Foreign currency impact	0	0
Balance at the end of the period	2,744	2,884	2,657
Accumulated benefit obligation at end of year	2,744	2,884
Change in fair value of plan assets
Balance at the beginning of the period	1,631	1,325
Actual return on plan assets	199	203
Participant contributions	0	0
Employer contributions	153	226
Plan transfer and acquisitions	0	0
Benefit payments	(128)	(123)
Actual expenses	0	0
Foreign currency impact	0	0
Balance at the end of the period	1,855	1,631	1,325
Market related value at end of year	1,765	1,566
Funded status	(889)	(1,253)
Unrecognized prior-service cost	12	0
Unrecognized loss	1,219	1,591
Net amount recognized	342	338
Other [Member]
Change in projected benefit obligation
Balance at the beginning of the Period	1,323	1,063
Service cost	18	14	15
Interest cost	45	48	51
Participant contributions	1	1
Plan amendment	0	0
Curtailments	(1)	0
Plan transfer and acquisitions	0	0
Actuarial loss (gain)	1	(23)
Benefit payments	(44)	(42)
Actual expenses	(1)	0
Change in discount rate	(85)	238
Foreign currency impact	(5)	24
Balance at the end of the period	1,252	1,323	1,063
Accumulated benefit obligation at end of year	1,177	1,241
Change in fair value of plan assets
Balance at the beginning of the period	1,009	853
Actual return on plan assets	34	111
Participant contributions	1	1
Employer contributions	55	71
Plan transfer and acquisitions	0	0
Benefit payments	(44)	(42)
Actual expenses	(1)	0
Foreign currency impact	7	15
Balance at the end of the period	1,061	1,009	853
Market related value at end of year	1,061	1,009
Funded status	(191)	(314)
Unrecognized prior-service cost	3	4
Unrecognized loss	402	491
Net amount recognized	$ 214	$ 181