Employee Benefits Amounts recognized in Accumulated other comprehensive loss that have not yet been recognized (Details 3) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
U.K. [Member]
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	$ 2,012	$ 1,981
Prior service cost	24	24
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost	2,036	2,005
U.S. [Member]
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	1,219	1,591
Prior service cost	12	0
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost	1,231	1,591
Other [Member]
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost
Net loss	402	491
Prior service cost	3	4
Amounts recognized in Accumulated other comprehensive loss unrecognized as components of net periodic benefit cost	$ 405	$ 495