Employee Benefits (Fair Value Measurements Using Significant Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Assets:
Fair value as of December 31, 2012	$ 6,980	$ 8,691
Purchases	3,091	5,334
Sales	(60)	(119)
Unrealized gains	(16)	(93)
Realized gain/(loss)	(165)	(325)
Fair value as of December 31, 2013	7,564	6,980
U.S. Pension Plan | Alternative Investments
Assets:
Fair value as of December 31, 2012	19	19
Purchases	12
Sales	0
Purchases and sales, net		0
Unrealized gains	1	0
Fair value as of December 31, 2013	32	19
U.S. Pension Plan | Private Equity
Assets:
Fair value as of December 31, 2012	2	2
Purchases	0
Sales	0
Purchases and sales, net		0
Unrealized gains	0	0
Fair value as of December 31, 2013	2	2
U.K. Pension Plan | Alternative Investments
Assets:
Fair value as of December 31, 2012	39	32
Purchases	3
Sales	0
Purchases and sales, net		3
Unrealized gains	1	4
Fair value as of December 31, 2013	43	39
Non-US Pension Plan (Excluding U.K.) [Member] | Insurance Group Annuity Contract
Assets:
Fair value as of December 31, 2012	61	57
Purchases	13
Sales	(5)
Purchases and sales, net		4
Unrealized gains	1	0
Fair value as of December 31, 2013	$ 70	$ 61