Employee Benefit Plans Employee Benefit Plans - Net Periodic Benefit Cost (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6	$ 7	$ 10
Interest cost	54	61	63
Expected return on plan assets	(74)	(74)	(75)
Net amortization	48	34	20
Net periodic benefit cost	34	28	18
Other Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	9	7	7
Interest cost	25	28	31
Expected return on plan assets	(30)	(30)	(30)
Net amortization	8	4	18
Net periodic benefit cost	$ 12	$ 9	$ 26