Employee Benefit Plans, Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity Securities [Member]
Employee Benefit Plans (Textual)
Percentage of equity securities in target allocations for plan assets		70.00%
Debt Securities [Member]
Employee Benefit Plans (Textual)
Percentage of equity securities in target allocations for plan assets		30.00%
Pension Plans [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[1]	$ 2,236	$ 2,428	$ 2,097
Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		909	1,078
Pension Plans [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		1,327	1,350
Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | US Companies [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[2]	497	571
Pension Plans [Member] | US Companies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[2]	497	571
Pension Plans [Member] | US Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[2]	0	0
Pension Plans [Member] | US Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[2]	0	0
Pension Plans [Member] | International Companies [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		160	188
Pension Plans [Member] | International Companies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		159	187
Pension Plans [Member] | International Companies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		1	1
Pension Plans [Member] | International Companies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Preferred Stock [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		4	4
Pension Plans [Member] | Preferred Stock [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		4	4
Pension Plans [Member] | Preferred Stock [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Preferred Stock [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | International Growth [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		97	118
Pension Plans [Member] | International Growth [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		97	118
Pension Plans [Member] | International Growth [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | International Growth [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Index Funds [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[3]	76	85
Pension Plans [Member] | Index Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[3]	76	85
Pension Plans [Member] | Index Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[3]	0	0
Pension Plans [Member] | Index Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[3]	$ 0	$ 0
Pension Plans [Member] | Index Fund - Equity Securities [Member]
Employee Benefit Plans (Textual)
Defined benefit plan, actual plan asset allocations		60.00%	70.00%
Pension Plans [Member] | Index Fund - Debt Securities [Member]
Employee Benefit Plans (Textual)
Defined benefit plan, actual plan asset allocations		40.00%	30.00%
Pension Plans [Member] | Corporate Debt Instruments [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		$ 284	$ 272
Pension Plans [Member] | Corporate Debt Instruments [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Corporate Debt Instruments [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		284	272
Pension Plans [Member] | Corporate Debt Instruments [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | US Treasury Securities [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		45	45
Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		45	45
Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Other Government Securities [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		138	144
Pension Plans [Member] | Other Government Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Other Government Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		138	144
Pension Plans [Member] | Other Government Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Defined Benefit Plan, Common Collective Trust [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[4]	609	621
Pension Plans [Member] | Defined Benefit Plan, Common Collective Trust [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[4]	0	0
Pension Plans [Member] | Defined Benefit Plan, Common Collective Trust [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[4]	609	621
Pension Plans [Member] | Defined Benefit Plan, Common Collective Trust [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[4]	$ 0	$ 0
Pension Plans [Member] | Common Collective Trusts - Equity Securities [Member]
Employee Benefit Plans (Textual)
Defined benefit plan, actual plan asset allocations		70.00%	80.00%
Pension Plans [Member] | Common Collective Trusts - Debt Securities [Member]
Employee Benefit Plans (Textual)
Defined benefit plan, actual plan asset allocations		30.00%	20.00%
Pension Plans [Member] | Pooled Separate Accounts [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[5]	$ 190	$ 192
Pension Plans [Member] | Pooled Separate Accounts [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[5]	0	0
Pension Plans [Member] | Pooled Separate Accounts [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[5]	190	192
Pension Plans [Member] | Pooled Separate Accounts [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets	[5]	$ 0	$ 0
Pension Plans [Member] | Pooled Separate Accounts - Equity Securities [Member]
Employee Benefit Plans (Textual)
Defined benefit plan, actual plan asset allocations		50.00%	50.00%
Pension Plans [Member] | Pooled Separate Accounts - Debt Securities [Member]
Employee Benefit Plans (Textual)
Defined benefit plan, actual plan asset allocations		50.00%	50.00%
Pension Plans [Member] | Private Funds [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		$ 87	$ 101
Pension Plans [Member] | Private Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Private Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		87	101
Pension Plans [Member] | Private Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Insurance Contract [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		18	18
Pension Plans [Member] | Insurance Contract [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Insurance Contract [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		18	18
Pension Plans [Member] | Insurance Contract [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Interest and Dividends Receivable [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		5	5
Pension Plans [Member] | Interest and Dividends Receivable [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		5	5
Pension Plans [Member] | Interest and Dividends Receivable [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Interest and Dividends Receivable [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Cash and Cash Equivalents [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		40	86
Pension Plans [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		40	85
Pension Plans [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	1
Pension Plans [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Securities Transactions Payable, Net [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		(14)	(22)
Pension Plans [Member] | Securities Transactions Payable, Net [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		(14)	(22)
Pension Plans [Member] | Securities Transactions Payable, Net [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		0	0
Pension Plans [Member] | Securities Transactions Payable, Net [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Values of Qualified Pension Plan Assets
Fair value of qualified pension plan assets		$ 0	$ 0

[1] Plan assets include only the assets associated with pension plans subject to legal minimum funding standards. Plan assets associated with U.S. nonqualified pension plans are not included here because they are not protected from our creditors and therefore cannot be reflected as a reduction from our obligations under the pension plans. As a result, the reconciliation of funded status does not reflect the effect of plan assets that exist for all of our defined benefit plans. See Note 19 for the assets associated with certain U.S. nonqualified pension plans.

[2] Equity securities are held in a wide range of industrial sectors, including consumer goods, information technology, healthcare, industrials, and financial services.

[3] This class includes primarily investments in approximately 60 percent equities and 40 percent bonds as of December 31, 2018. As of December 31, 2017, this class included primarily investments in approximately 70 percent equities and 30 percent bonds.

[4] This class includes primarily investments in approximately 70 percent equities and 30 percent bonds as of December 31, 2018. As of December 31, 2017, this class included primarily investments in approximately 80 percent equities and 20 percent bonds.

[5] This class includes primarily investments in approximately 50 percent equities and 50 percent bonds as of December 31, 2018 and 2017.