Employment Benefit Plans Level 3 Rollforward (Details) (Successor [Member], Pension Plans, Defined Benefit [Member], USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Ending balance	$ 2,013,000,000	[1]	$ 1,807,000,000	[2]
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	130,000,000	[2],[3]	120,000,000
Actual return on plan assets still held at reporting date	1,000,000		13,000,000
Actual Return on Plan Assets Sold During Period	3,000,000
Purchases, Sales, and Settlements	(102,000,000)		(1,000,000)
Transfers out of Level 3			(2,000,000)
Ending balance	32,000,000	[1],[3]	130,000,000	[2],[3]
US Government Agencies Debt Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Ending balance	13,000,000		151,000,000
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	1,000,000	[3]	1,000,000
Actual return on plan assets still held at reporting date	0		0
Actual Return on Plan Assets Sold During Period	0
Purchases, Sales, and Settlements	(1,000,000)		0
Transfers out of Level 3			0
Ending balance	0	[3]	1,000,000	[3]
Real Estate [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Ending balance	32,000,000		129,000,000
Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance	129,000,000	[3]	116,000,000
Actual return on plan assets still held at reporting date	1,000,000		13,000,000
Actual Return on Plan Assets Sold During Period	3,000,000
Purchases, Sales, and Settlements	(101,000,000)		0
Transfers out of Level 3			0
Ending balance	32,000,000	[3]	129,000,000	[3]
Collateralized Mortgage Backed Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Ending balance	1,000,000		32,000,000
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance			3,000,000
Actual return on plan assets still held at reporting date			0
Purchases, Sales, and Settlements			(1,000,000)
Transfers out of Level 3			(2,000,000)
Ending balance	$ 0	[3]	$ 0	[3]

[1] Excludes $1 million accrued for dividend and interest receivable.

[2] Excludes $10 million accrued for dividend and interest receivable.

[3] See Note 2 to the Consolidated Financial Statements under the heading “Fair Value Measurements” for a definition of each of these levels of inputs.