Employment Benefit Plans Plan Assets (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Accrued dividend and interest receivable	$ 1,000,000		$ 1,000,000
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,342,000,000	[1]	2,490,000,000	[2]
Pension Benefits | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,196,000,000	[1],[3]	2,300,000,000	[2],[3]
Pension Benefits | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	146,000,000	[1],[3]	190,000,000	[2],[3]
Pension Benefits | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[1],[3]	0	[2],[3]	32,000,000
Pension Benefits | Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	30,000,000		16,000,000
Pension Benefits | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	30,000,000	[3]	16,000,000	[3]
Pension Benefits | Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Registered investment companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	28,000,000		60,000,000
Pension Benefits | Registered investment companies [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	28,000,000	[3]	60,000,000	[3]
Pension Benefits | Registered investment companies [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Registered investment companies [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | US Government Agencies Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	13,000,000		10,000,000
Pension Benefits | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	13,000,000	[3]	10,000,000	[3]
Pension Benefits | US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Collateralized Mortgage Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	6,000,000		2,000,000
Pension Benefits | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	6,000,000	[3]	2,000,000	[3]
Pension Benefits | Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	97,000,000		162,000,000
Pension Benefits | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
Pension Benefits | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	97,000,000	[3]	162,000,000	[3]
Pension Benefits | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3]	0	[3]
UNITED STATES | Pension Benefits | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,091,000,000	[4]	2,240,000,000	[5]
UNITED STATES | Pension Benefits | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	2,091,000,000	[3],[4]	2,240,000,000	[3],[5]
UNITED STATES | Pension Benefits | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3],[4]	0	[3],[5]
UNITED STATES | Pension Benefits | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3],[4]	0	[3],[5]
International [Member] | Pension Benefits | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	77,000,000	[4]
International [Member] | Pension Benefits | Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	77,000,000	[3],[4]
International [Member] | Pension Benefits | Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	0	[3],[4]
International [Member] | Pension Benefits | Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets Excluding Accrued Dividend And Interest Receivable	$ 0	[3],[4]

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

[2] Excludes $1 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.

[4] As of December 31, 2014, three equity securities each exceeded 10 percent of total plan assets. These investments represent approximately 43 percent of total plan assets.

[5] As of December 31, 2013, four U.S. equity securities each exceeded 10 percent of total plan assets. These investments represented approximately 62 percent of total plan assets.