Employee Benefit Plans Employee Benefit Plans - Level 3 Rollforward (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Pension [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	$ 1,171		$ 1,012		$ 931
Pension [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	86	[1]	96	[1]
Pension [Member] | Limited Partnership Interests [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	86	[2]	96	[2]
Pension [Member] | Limited Partnership Interests [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	96	[1],[2]	71		84
Actual return on plan assets still held	16		7		7
Purchases, sales, distributions and settlements	(26)		18		(20)
Plan assets at fair value, end of year	86	[1],[2]	96	[1],[2]	71
Other Postretirement [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	486		424		384
Other Postretirement [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	6	[1]	7	[1]
Other Postretirement [Member] | Limited Partnership Interests [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, end of year	6	[2]	7	[2]
Other Postretirement [Member] | Limited Partnership Interests [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Plan assets at fair value, beginning of year	7	[1],[2]	6		7
Actual return on plan assets still held	1		0		1
Purchases, sales, distributions and settlements	(2)		1		(2)
Plan assets at fair value, end of year	$ 6	[1],[2]	$ 7	[1],[2]	$ 6

[1] Refer to Note 12 for additional discussion regarding the three levels of the fair value hierarchy.

[2] Limited partnership interests include several funds that invest primarily in buyout, growth equity, venture capital and real estate.