Employee Benefit Plans, Net Cost (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plan, Defined Benefit
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 47	$ 39	$ 32
Interest cost	89	100	102
Expected return on plan assets	(124)	(118)	(120)
Amortization of net loss	17	10	0
Settlements	(1)	0	1
Net cost recognized	28	31	15
Retiree Health and Welfare Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	1
Interest cost	12	13	14
Amortization of prior service credits	(1)	0	0
Amortization of net loss	5	1	0
Net cost recognized	$ 17	$ 15	$ 15